SQLite is the lighter SQL database system. Aside from the advantage that you dont need Pervasive, Access, mySQL et al running, you can create the database programatically (as opposed to having it present beforehand).
The downside is there are fewer commands to make things simple - this means almost all commands need to be carried out using SQL (so its time to start swatting).
At the moment I'm still deciding how best to get the data back into DBPro (SQLite returns all query results in one go), so there probably wont be anything soon...