The Hypernode team of byte a hosting company in the Netherlands created a very useful n98-magerun plugin to detect outdated modules in your shop.
You can find the plugin on github.
The plugins adds two new command to your command list:
The command sys:modules:list-updates command checks your locally installed modules against a list of 500 community modules and prints all module which are outdated.
The other command
sys:info:patches prints all not applied official patches.
Thanks Byte for this useful n98-magerun plugin.