Hey KCIREVAM:
Well, you could get the book
The Divelight Companion which has a lot of diagrams, explanations, how-to's and where to get stuff information. I have this book and I love it. I'd venture to say that most DIY light builders have this book and like it as well.
With that said though, saving a few bucks as well, the Search Function above will yield any and almost all the information that you need. The names to look for, and in no particular order of likeness, are Packhorse, 350xfire, MrSpock, bronk, and rescue15 to name a few (well, ok I ordered them with some likeness in mind). I must give a special shout out to Packhorse though, because he not only makes LED canister lights and the such but he is continuously striving to make the next brightest, whitest, most economical, and most reliable LED light that can be had. Plaque and trophy to follow.
So, these will be freebees. I have done an advanced search on the forum, specifying DIY section and keywords
DIY light and
DIY canister light. 450 and 130 returns respectively. Also, use the search function in the red bar above and not the blue one. Oh, and Packhorse started a thread in DIY on where to get parts; this is handy because the places are up to date.
If you have any questions, the Search function will be your best friend. It is somewhat temperamental but you can find your answers here. And I highly doubt that you will have a problem that hasn't been had and conquered by others, and more responses will come when you want to ask a question or discuss an opinion about the best for your needs. Just put some thought into it.
Well, good luck and please post your progress and finished light here.
With kind regards,
Thomas