Yeah the Pistons have cap space for the 09 offseason... but what for?? Next summer's FA class is headlined by Andre Miller, Mike Bibby, Hedo Turkoglu, and an old Steve Nash/Jason Kidd. No all-star players for a team that's going to need them to stay afloat, unless Carlos Boozer or Kobe Bryant opt out of their contracts, which you can't bank on.
If they made this trade with 2010 in mind, that's also foolish. The big guys on the market who are still relatively young are LeBron James, Dwyane Wade, Chris Bosh, Joe Johnson, Josh Howard (option), Michael Redd (option), and Amare Stoudemire (option). Three of those seven have player options that they're likely to exercise, and for the remainders the Pistons will have to bid against big city teams like the Bulls, Nets, Knicks, and Heat, as well as playoff teams that will be desperately looking for that big piece to push them over the top. I favor the field as opposed to the Pistons.
The Pistons are in a ditch now. The best they can do now is flip Iverson's contract somewhere else for a good draft pick and rebuild that way.