paying taxes

you guys pay quarterly tax estimates?

i just talked to a tax attorney today who says I will need to pay every 1/4 and that my wins/losses will offset previous payments so in the end of the year I will get a refund/owe more which seems kind of rediculous. isnt it just easier to pay it all in the end of the year? or will I get penalties for this?

also, how is the IRS supposed to know if I my "income/winnings" is still in the poker site?