Is there a tool/website to compare package status in different Linux distributions?

I am currently looking for a website or a tool that would allow me to compare the package state of a particular software in different Linux distributions. For instance, which version of gimp is provided by Mint, Ubuntu, Debian Sid and Fedora 18? An immediate interest would be to be able to avoid reinventing the wheel when packaging software (for instance re-use patches from other distros).