A little while ago I wrote a long calculus proof about why .999... = 1 but I can't find it.
But it's true. Think about it this way:
1 - .999... = 1/inf
1/inf = 0 (
by definition).
For the "proof" that 3 = 1, my trusty TI-89 says that ln[e^(3*i*pi}] = i*pi not 3*i*pi. I don't know much about imaginary numbers, so don't ask me why.
For the "proof" that 2=1, that's easy. At one point you divide both sides by (a-b). a = b therefore a-b = 0 and you are dividing by 0.