I, too, discovered 5/22 that I could not update my blog. My host is BlueHost, and I also had the “seotoos.com” hack. Turns out that 3 files were hacked on May 18, 2009 @ 4:24PM. My index.php (like everyone else’s); then in the plugins folder, both akismet and hello (the “hello dolly” WordPress plugin) both had versions with a “.new” extension. I replaced the index.php with a copy I had from 6/21/2008 on my computer and deleted the akismet.new and hello.new from the plugins folder (in the wp-content folder).
For now, my blog *appears* to be operating OK (until the next hack). In the meantime, I’m going to go back in and change my passwords…