NFL players aren't paid like the rest of us. Whatever our salary is gets spread out over a 52-week year, usually with a paycheck every two weeks. NFL players get paid per game, with their last game check coming two weeks after the season ends. So generally, players will not feel the hit of a lockout (assuming one happens) until regular season games start getting canceled.
Players do get bonuses for participating in the off-season workouts, so assuming those don't happen, players will miss out on that money. But it's not much compared to their game checks.
Another thing to keep in mind is that several NFL players qualify for roster bonuses in March. In a Todd Archer blog, he wrote that there are a few Cowboys who are due roster bonuses soon after the new league year begins (the 2011 league year starts when a new collective bargaining agreement is reached). For example, Cowboys wide receiver Dez Bryant is due a $1 million roster bonus. He'll get that five days after the new CBA is signed. Montrae Holland is also due $500,000 on the fifth day; Bradie James and Jason Witten are due the same amount on the 15th day of the new league year.
It's something to keep in mind as the negotiations continue.