Seriously, my last tax post (Re: Estimated tax payments)

[LondonBroil]

I just did my 2004 taxes declaring my net winnings as "other income" on line 21 of my 1040. This isn't a discussion about how I'm a horrible person because I didn't declare gross winnings and deduct my losses. Anyway, I ended up owing $1600 in taxes and because I owe over $1,000, I'm going to have to pay penalties as well. I don't feel like doing this again next year at this time (paying the penalty).

My question is to those who pay their taxes quarterly, seeing as how the first payment is due very soon (4/15). The tax booklet says that you must make 4 equal payments in April, June, September, and January. Now, my question is, how am I supposed to know exactly how much to pay each quarter seeing as how I have no idea how much I'm going to make in the months ahead? I coud run very well in the first quarter than go on a 3 month losing streak!

Also, why does it go April, June, September, January? Shouldn't it go April, July, October, January?

Anyone who does estimated quarterly taxes please respond as I do not have much time to complete this.