Greasefire2 is my try at reviving the original greasefire addon after the shutdown of userscripts.org and skrul.com.
Most of the work is from the original author skrul.
Greasefire2 for Firefox: https://addons.mozilla.org/en-US/firefox/addon/greasefire2/
The original Firefox extension can be downloaded at https://addons.mozilla.org/en-US/firefox/addon/greasefire/
The Chrome extension is not yet complete, but grab the source and give it a try!
You can find a mirror copy of the discussion forums at http://userscripts-mirror.org/forums/5.html