Dear Hype:
I agree with the answer posted by Vhehn. The general rule on capital losses is that you first offset them against capital gain (and if you don't have capital gain, then obviously there's no offset), and then you can deduct the excess capital loss against ordinary income to the extent of $3k per year. The remaining capital loss is carried over to the next taxable year, where the same treatment ensues. This will continue until the capital loss carryforward is either consumed or you die.
If there is a valid, existing mark-to-market election in place (and it doesn't sound like there is), there are different rules. Basically, the gains and losses are treated as ordinary gains/losses (as distinct from capital gain/loss), for which there are different tax rules.