If you use Joomla, it's important to keep your installation up-to-date. Last summer we went through a process with many of our customers to get everyone updated to the then-current 1.5.14. Sadly, 1.5.15 was released about 2 weeks after we finished!
Recently a customer's web site running 1.5.14 got compromised. We're recommending that everyone running a Joomla site update to 1.5.15 as soon as possible.
Now for the good news: our programmer Todd found 2 Joomla modules that make updating Joomla much easier. One tool compares your installed Joomla files against a clean Joomla install for your version, and warns you of any changes which might cause problems in an update. The other tool applies the update for you.
And the best for last: Todd wrote an excellent step-by-step tutorial for updating your Joomla install: https://members.swcp.com/wiki/Updating_Joomla
If you use Joomla, check it out, update ASAP, and please contact us if you run into any problems!