I have been doing colorizations for about three years and found it much easier than I thought. It can be a bit time consuming and research is a major time factor. The results can be fantastic and very rewarding. You can start with just a PC/Mac and a mouse, if you get more serious I would suggest getting a drawing tablet as it will greatly improve your technique. I would suggest you try it with the mouse first and see if this is something that you want to invest time into.
I have to say I really enjoy it and find the outcome a real thrill.
Zuzah has some great tutorials, I have a book on the subject and you can also get a copy of Photoshop CS2 for free. If you think you might be interested it would be worth spending some time exploring it. Let us know if you have questions, you can either post them here, or PM.
Good luck!
David