What is it?
Rockstar decided to remove the coronas from dropped weapons when San Andreas came around, it was a nice feature in III/VC that gave the game atmosphere. This mod adds coronas to weapons similar to III/VC, although not perfect, I think it suits the game and looks pretty good. Hey, it's better than not releasing it at all!
Simply put the files inside gta3.img using an IMG tool. Or you could take the easy way by installing it with Mod Loader (recommended).
GTA Garage is currently being worked on by admins and right now no mods are being accepted into the site while they work on it. So in the mean time, you can download the mod from the GTA Forums page.