According to the official lifecycle calendar at http://www.mysql.com/about/legal/lifecycle/#calendar, active support for MySQL 5.0 (including regular binary updates) will end on December 31st, 2009, which is about 3 weeks away.
Many folks are still using MySQL 5.0.45, as until October that was the package that came with RedHat. That was released in July 2007, over 2 years ago!
Upgrading to MySQL 5.1 is not difficult, though it requires more steps than just upgrading the packages.
There is a list with all the changes made that might affect the upgrade process at http://www.pythian.com/news/1414/new-in-mysql-51-sheeris-presentation/. This includes which variable names have been deprecated and changed, as well as how to upgrade stored procedures, functions, triggers and views so they work properly in MySQL 5.1.
I hope this helps folks out, and please feel free to ask any questions. Pythian is available to assist you in the upgrade process, just contact us if you want to engage our help.
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