The Sports Guru from The Mile High Report was kind enough to put together some great info on the salary cap in 2009 and 2010, which is possibly an uncapped season.
I'm going cut & paste what he wrote verbatim. This should clear up any inconsistencies you've been reading about.
First, since 2009 is the final year of the cap, teams CANNOT take huge cap numbers, change them to bonuses and spread the hit out over future years. If you are a team with a receiver set to count 13 mil against the cap, chances are he’s going to get cut. Hence the reason Brett Favre won’t "commit" to 2009 for "several weeks. The Jets are 10 Mil over the cap, reportedly, and he is hoping they cut him.
Guru goes on to give us the ramifications of an uncapped 2010 season.
Free Agency Requirements Raised From 4 to 6 years -- Currently, players who are unsigned and have finished at least four NFL seasons are free. In the 2010 market, players will be free if they are unsigned after at least their sixth NFL season. In other words, 2009 would have to be a player's sixth season, and he would have to enter 2010 unsigned. Let's use Cleveland wide receiver Braylon Edwards as an example. In his original rookie contract, signed in 2005, the final year is 2009, which would be his fifth NFL season. Ordinarily, he'd be a free-agent in 2010 -- if the team didn't sign him before then or place a franchise tag on him. But under the 2010 rules, he won't be a free-agent.
Three 'Franchise'-type Tags Instead Of One -- Right now teams can designate one player each year as a "Franchise" player(average of top-5 salaries at position) or "Transition" player(average of top-10 salaries at position), restricting his ability to negotiate with other teams. Should the League go uncapped in 2010 and 2011 each team would have access to 1-Franchise Tag and 2-Transition Tags. Not only would a player have to wait 6 years just to get to Free Agency, they would have a much greater likelihood of getting restricted even further with one of these tags.
Top 8 Teams Will Be Restricted -- If the uncapped year is reached, the teams with the best eight records in football in 2009 will be severely restricted from jumping into the pool. It's still not precisely determined how the system would work, but let's say the Patriots are one of the top eight and want to sign a free-agent to a five-year, $20-million contract. They'd have to lose their own player or players to contracts totaling $20 million before they could sign the free-agent they want.
Conceptually, that's how this clause in the deal is going to work, but the exact mechanics of it are not clear yet. The purpose is very clear: The best teams are going to have tight leashes in free agency. And I can tell you from talking to a few traditionally good teams at the league meetings last week, they're not happy about it.
Digest and discuss. I'll jump in in a bit.