samsung Galaxy s firmware I had a message about running out of space on my GT-i9000 so like a fool I started deleting things...turns out I deleted most of my operating system is there somewhere I can download the os rather than sending back to the manufacturer (and is this the firmwear)
Samfirmware.com or XDA are your best bets.  If you need instructions for flashing with Odin or recovery, we have lots of questions on that so just do a search :)