Great module, I think it may become my time tracking module of choice.

I've just migrated from time_tracker - here's some SQL that people might find useful to migrate their data to YATT:

INSERT INTO yatt(nid,cid,uid,note,start,stop,created,billable)
SELECT nid, cid, uid, '' AS note, timestamp -  ( duration *60 *60 ) AS start , timestamp AS stop , timestamp AS created, 0 AS billable
FROM time_tracker_entry