user11475: I want to buy an arduino development board which has facility to remove its chip and insert a new one anytime. I want to use multiple chips in a single board for different purposes.
If it is not possible, Please suggest me any alternative.

user10794: You could get an ATmegaXX8 target board from Evil Mad Scientist. That has (or can have) a ZIF socket so you can easily remove the chip without bending its legs.

That's around $US 3 for the board, $2 for the ZIF socket, $1 for the crystal, 45 cents for the ICSP header.
You can put an Atmega328P into the socket (same chip as on the Uno). Note that some soldering is required. You would need to solder on the ZIF socket, the ISP header, and make up an FTDI header if you wanted to easily program it from the IDE. 
You would also need (or it would be helpful to have) a 16 MHz crystal along with 2 x 18 pF capacitors. They have them for sale at that site.
You would also need a 10 k pull-up resistor for Reset, a couple of 0.1 µF decoupling capacitors, and another 0.1 µF capacitor for handling reset via the FTDI interface - if you use it.
If you want to program serially (and do serial debugging) you need some sort of USB interface, such as an FTDI cable or board.
Example FTDI Serial TTL-232 USB Cable.

That is around $US 18. (Of course, you only need to buy the cable once, so this is a one-time cost).
You would need to solder in 6 header pins in a line to plug that into (on the prototyping area) and then run appropriate wires to Tx/Rx/Gnd/5V and Reset via the 0.1 µF capacitor I mentioned.
Adafruit have an Arduino bootloader-programmed chip (Atmega328P) for $US 6.
All-up it would probably cost you around $US 30 to put it together. (The FTDI cable is a once-off cost, as you can use that on multiple projects).

Other vendors will probably have similar products.

user6936: The ultimate solution would be to build it yourself! 

Arduino has an excellent step by step guide on how to build a standalone Arduino, using a ATMega328, on a breadboard. Now everything is removable, not just the chip.
Note that there is one slight error in the guide, which I have highlighted here, Arduino Standalone - photo shows incorrect pin wired to MOSI.
There is a video on how to achieve, more or less, the same thing, 1-Day Project: Build Your Own Arduino Uno for $5.

user2881: Only the Arduino Uno has a socketed IC chip. All the rest are using soldered SMD ICs.

11475: <p>I want to buy an arduino development board which has facility to remove its chip and insert a new one anytime. I want to use multiple chips in a single board for different purposes.</p>

<p>If it is not possible, Please suggest me any alternative.</p>
 10794: <p>You could get an <a href="http://shop.evilmadscientist.com/productsmenu/tinykitlist/74-atmegaxx8" rel="nofollow noreferrer">ATmegaXX8 target board</a> from Evil Mad Scientist. That has (or can have) a ZIF socket so you can easily remove the chip without bending its legs.</p>

<p><a href="https://i.stack.imgur.com/NaC8r.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NaC8r.jpg" alt="AtmegaXX8 target board"></a></p>

<p>That's around $US 3 for the board, $2 for the ZIF socket, $1 for the crystal, 45 cents for the ICSP header.</p>

<p>You can put an Atmega328P into the socket (same chip as on the Uno). Note that <em>some soldering is required</em>. You would need to solder on the ZIF socket, the ISP header, and make up an FTDI header if you wanted to easily program it from the IDE. </p>

<p>You would also need (or it would be helpful to have) a 16 MHz crystal along with 2 x 18 pF capacitors. They have them for sale at that site.</p>

<p>You would also need a 10 k pull-up resistor for Reset, a couple of 0.1 µF decoupling capacitors, and another 0.1 µF capacitor for handling reset via the FTDI interface - if you use it.</p>

<p>If you want to program serially (and do serial debugging) you need some sort of USB interface, such as an FTDI cable or board.</p>

<p>Example <a href="http://www.adafruit.com/products/70" rel="nofollow noreferrer">FTDI Serial TTL-232 USB Cable</a>.</p>

<p><a href="https://i.stack.imgur.com/9KNFw.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9KNFw.jpg" alt="FTDI cable"></a></p>

<p>That is around $US 18. (Of course, you only need to buy the cable once, so this is a one-time cost).</p>

<p>You would need to solder in 6 header pins in a line to plug that into (on the prototyping area) and then run appropriate wires to Tx/Rx/Gnd/5V and Reset via the 0.1 µF capacitor I mentioned.</p>

<p>Adafruit have an <a href="http://www.adafruit.com/products/123" rel="nofollow noreferrer">Arduino bootloader-programmed chip (Atmega328P)</a> for $US 6.</p>

<p>All-up it would probably cost you around $US 30 to put it together. (The FTDI cable is a once-off cost, as you can use that on multiple projects).</p>

<hr>

<p>Other vendors will probably have similar products.</p>
 6936: <p>The ultimate solution would be to build it yourself! </p>

<p><a href="https://i.stack.imgur.com/EYXT3.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EYXT3.jpg" alt="Standalone Arduino"></a></p>

<p>Arduino has an excellent step by step guide on how to build a <a href="https://www.arduino.cc/en/main/standalone" rel="nofollow noreferrer">standalone Arduino</a>, using a ATMega328, on a breadboard. Now everything is removable, not just the chip.</p>

<p>Note that there is one slight error in the guide, which I have highlighted here, <a href="https://arduino.stackexchange.com/questions/10392/arduino-standalone-photo-shows-incorrect-pin-wired-to-mosi">Arduino Standalone - photo shows incorrect pin wired to MOSI</a>.</p>

<p>There is a video on how to achieve, more or less, the same thing, <a href="https://www.youtube.com/watch?v=sNIMCdVOHOM" rel="nofollow noreferrer">1-Day Project: Build Your Own Arduino Uno for $5</a>.</p>
 2881: <p>Only the Arduino Uno has a socketed IC chip. All the rest are using soldered SMD ICs.</p>
