We'll be converting to UTF-8 when we restructure the database for the 1.5 upgrade. This will be sometime in the next couple of months.
1.5 supports on the fly conversion of the old text blobs on load, so what needs to be converted is the usernames, titles, comments, etc in the other support tables. This should be a relatively minor expense of the overall conversion (which is necessary as it will be removing some of the nasty bottlenecks of our current database layout).
-- brion vibber (brion @ pobox.com)