Thanks for the tips, everyone. 
I actually tried figuring everything out on my own, but after a few hours of frustration, I gave up. I do think I can handle the quarterly taxes in 2006, once I get some advice from a tax professional on how to estimate the quarterly payments. This year is further complicated because I am buying a home, and now I will be able to deduct mortgage interest and property tax from my income. So, in 2006 I will start itemizing my deductions, and I’ll start paying quarterly taxes…. Oh, and if I get married this year or next year, that will probably affect things too. 
Thanks again for the advice. :satisfied