user3563: I bought an Arduino-on-breadboard kit. I have several PCs with serial ports, and now I'm being told I need a USB-to-serial converter. I thought I was ready to start uploading sketches, so how can I do this?
I'm able to understand serial communications and am capable of wiring a MAX232 chip into a breaduino if necessary, but I'm not sure it will work, so to save some time I'm asking, mostly because I was unable to figure it out with Google searches alone.
PS: I also have a stk500, but then I would be out of the easiness of using Arduino sketches and the programming language. I need the fastest route to prototyping/testing my sketches.

user1576: An RS232 port wired via a level converter (as you mentioned max232) and a 1uF capacitor between RTS and "Arduino reset pin" Getting started with Arduino.
The capacitor is to trigger a reset on the Arduino so the bootloader kicks in and awaits a "Arduino sketch" via the serial port.
Your setup is AKA "Arduino Bare bone".

3563: <p>I bought an Arduino-on-breadboard kit. I have several PCs with serial ports, and now I'm being told I need a USB-to-serial converter. I thought I was ready to start uploading sketches, so how can I do this?</p>

<p>I'm able to understand serial communications and am capable of wiring a <a href="https://en.wikipedia.org/wiki/MAX232" rel="nofollow noreferrer">MAX232</a> chip into a <a href="https://hackaday.io/project/43857/gallery#93070cbab9a55ed645fc2aa7dc3c54c3" rel="nofollow noreferrer">breaduino</a> if necessary, but I'm not sure it will work, so to save some time I'm asking, mostly because I was unable to figure it out with Google searches alone.</p>

<p>PS: I also have a stk500, but then I would be out of the easiness of using Arduino sketches and the programming language. I need the fastest route to prototyping/testing my sketches.</p>
 1576: <p><img src="https://i.stack.imgur.com/6a9HT.jpg" alt="enter image description here">An RS232 port wired via a level converter (as you mentioned max232) and a 1uF capacitor between RTS and "Arduino reset pin" <a href="http://tronixstuff.com/2010/06/14/getting-started-with-arduino-chapter-ten/" rel="nofollow noreferrer">Getting started with Arduino</a>.</p>

<p>The capacitor is to trigger a reset on the Arduino so the bootloader kicks in and awaits a "Arduino sketch" via the serial port.</p>

<p>Your setup is AKA "Arduino Bare bone".</p>
