Corrupted Mail.app / SQLite -- how to fix?

Mail.app on Lion has been behaving erratically, hanging sometimes. I open Console.app, and when starting Mail.app, I get the following.

2011/08/11 8:47:23.709 PM Mail: Using V2 Layout

2011/08/11 8:48:04.047 PM PubSubAgent: SQL Error: SQLITE_BUSY[5.0]: database is locked in "commit"

2011/08/11 8:48:04.047 PM PubSubAgent: SQLite::Exception "SQLITE_BUSY[5.0]: database is locked in "commit"" caught in void Foundation::AbstractTimer::_fire()

2011/08/11 8:48:04.051 PM PubSubAgent: AgentTask: Notified of fatal database error

2011/08/11 8:48:04.051 PM PubSubAgent: *** DATABASE IS BROKEN/STUCK: Moving aside and rebuilding ***

2011/08/11 8:48:31.662 PM Mail: SQL Error: SQLITE_BUSY[5.0]: database is locked in "SELECT * FROM Feeds WHERE rowID=?"

2011/08/11 8:48:31.662 PM Mail: SQLite::Exception "SQLITE_BUSY[5.0]: database is locked in "SELECT * FROM Feeds WHERE rowID=?"" caught in NSString* -[PSFeed identifier](PSFeed*, objc_selector*)

2011/08/11 8:48:31.662 PM Mail: Exception notifying PSClient delegate: PubSub SQLite::Exception: SQLITE_BUSY[5.0]: database is locked in "SELECT * FROM Feeds WHERE rowID=?" during NSString* -[PSFeed identifier](PSFeed*, objc_selector*)

2011/08/11 8:48:56.908 PM Mail: SQL Error: SQLITE_BUSY[5.0]: database is locked in "SELECT * FROM Feeds WHERE rowID=?"

2011/08/11 8:48:56.908 PM Mail: SQLite::Exception "SQLITE_BUSY[5.0]: database is locked in "SELECT * FROM Feeds WHERE rowID=?"" caught in NSString* -[PSFeed title](PSFeed*, objc_selector*)

2011/08/11 8:48:56.908 PM Mail: Exception notifying PSClient delegate: PubSub SQLite::Exception: SQLITE_BUSY[5.0]: database is locked in "SELECT * FROM Feeds WHERE rowID=?" during NSString* -[PSFeed title](PSFeed*, objc_selector*)

and

2011/08/11 8:50:06.013 PM Mail: SQLite::Exception "SQLITE_CORRUPT[11.0]: database disk image is malformed in "SELECT * FROM Authors WHERE rowID=?"" caught in NSString* -[PSAuthor name](PSAuthor*, objc_selector*)

I don't like "Fatal database error" and "broken" and "disk image malformed".... What can I do to fix this?