What exactly do you need to program the microcontrollers? Is it a socket that plugs into the computer? I'd love to learn to program them myself. I don't know C, but I learned to code in MATLAB in college and I taught myself to use VBA this past year at work. The principles are the same, I'd just have to learn the syntax. I do appreciate the offer for the programmed chip.
As long as you didn't let the magic smoke out of the circuit, there's still hope. Why use a pot when you need a constant resistance?
Here's the programmer I use.
USBtinyISP - Inexpensive USB AVR Programmer
It's cheap, and you can solder it yourself to get some experience. (Or you can buy one presoldered, but if you can't solder this, you shouldn't be doin this project.)
Also download AVR Studio. I have version 4.13, I don't know if there are newer ones, but this version works with the programmer I showed you above. You could always buy a brand name programmer, but they are anywhere from $50 to $100, and I figured, "Why spend the money when I can buy one for $20 that does the same thing? There are also some programs you need to make the programmer work correctly with AVR studio, but they're really easy. It's on the site, and it walks you through it. If you get those things, you'll be able to program any chip. (Well, any Amtel chip at least, I haven't tried adurinos)
Also, I order everything from DigiKey.com It's a (I think) wholesale distributor. I think they're used to very large orders, but I make small orders just fine. Great shipping too. It's really hard to find the correct things though, cause there is like 5 slightly different versions of everything. You REALLY have to know what you're looking for. But, I have all of the part numbers I used, so if you want to make sure you're getting the right stuff, I can look it over for you. Also, I'll type up a parts list when I'm done.
Anyway, start lookin up C programming. It's actually pretty easy. (Of course I say that, I know it lol) Like you said, once you know how to program, it's all syntax.
Ok, on to the business at hand. I finished my little "project box". The ones at Radio Shack didn't fit right, either too big or to small, so I made one. I put a small computer fan on the end so that the regulators don't get too hot. One thing I did forget to do was actually program the delays into the MCU, so that it takes 12ish hours to go through the whole cycle. But I still have the programming part set up on the breadboard, so it'll be done in a few. I'm going to install everything tonight, so I don't bug the fish by turning the light off in the middle of the day. Hopefully the day after tomorrow I'll have some time lapse video of the moonlights and stuff in action.
EDIT: Oh and on the use of the POT, I believe with the use of the variable voltage regulator, the calculation isn't exactly correct, so the POT helps you get the exact voltage you want. I could guess and stick a bunch of different resistors in there, but it's just easier this way.