I hope you have an up to date database backup, and your theme files.
Re-upload the latest wordpress files (currently 2.0.7), delete the database and create a fresh one with a “strong” password (make sure it’s different from your old one), re-install wordpress, then restore the database from the last good backup.
Then change your wordpress login passwords…
Just to be sure I would also suggest that you change your hosting login password as well.
It seems a pain, but unfortunately these things happen… there are some real ba****ds out there
As far as making sure it doesn’t happen again, make sure you keep wordpress up to date, and that all your passwords are “strong” ones (numbers, upper/lower case letters and ossibly special characters eg %$￡”)
