Here is a photo of my simple ISP dongle with the cover off:

Here are the schematics:

I use Bascom-AVR software to download my code into AVR chips. The demo version of Bascom-AVR allows you to download up to 2K of software into an AVR chip (the latest version may now allow 4k), which is more than enough for simple projects such as my rotary interface, my recoil interface and my rainbow LED circuit. Try to keep the ribbon cable short to insure reliability. Also you might have to adjust the BIOS LPT settings and software settings for your printer port. My neighbor recently borrowed my laptop and returned it with a crashed drive. I had some trouble getting the programmer to work after installing the new drive. There seems to be a conflict with the IBM Thinkpad software, so I just removed it and it now works again.

I finally had some luck extending the length of my programmer by switching to CAT5e cable. I used twisted pairs for the Clock, MISO and MOSI. I split the forth pair for Reset and Ground. I made sure that I kept the pairs twisted right up to the solder connections. I also dropped the resistors down to 220 ohms. Since I can access all my circuits from the coin door of my cab, I can now download new code from my desktop without moving my cab. Here is my new 12 foot programmer:


A close up shot of the pinout.


Update 10-04-2006
I built a new USB AVR ISP Programmer