There are some rumors that Adam Dunn could be had from the Nationals, but the Nats' GM says that he is not available:

"We are not trading Adam Dunn. That's as definitive as I can be . . . By no means is Adam Dunn on the trading block. We do not want to move Adam Dunn. We acquired him to keep him in the long-term. He's having an All-Star type of first half, he's a leader in the clubhouse and he's the anchor of the middle of our lineup."

Which makes total sense. For one thing, there isn't a team out there who (a) needs a bad defender/DH; (b) has the money to pay Dunn's contract through the end of 2010; and (c) has the kind of prospects to send back to Washington that would make the P.R. of it all (i.e. trading your big free agent splash just over three months into the season) worth the Nationals' while.

As Nats' watcher and NBC Washington contributor Chris Needham notes in this comments thread, the Nationals have been down this road before, last time with Alfonso Soriano. Many criticized Washington for not trading him during his career-year in 2006 and instead allowing him to become a free agent. What most people don't realize, however, is that Washington got two compensation picks for him in return. One of those pics is Jordan Zimmermann, who, unlike anything the Nats could have gotten for Soriano that July, is likely to be a part of the next good Nationals team.

Well, the first good Nationals team, but you see my point.