If you want them for gaming, don't bother. You can get a HD4670 for about the same price as one of those, and it will destroy those 8600's. If you're just wanting to run four monitors, grab these HD3450's for $40.
The gigabyte of memory on those cards would be wasted, and it's GDDR2 anyway, which slows it down even more. A regular 8600 GT runs about $50 on newegg any more.
I'm sorry, maybe its late and my eyes are tired but I assumed you were wanting them to SLI together. If you're wantign to put them in separate computers I still wouldn't buy them though. If the computers you are putting them in are just regular 2d computers (i.e., no gaming) save some money and get like a $30 card, or just use integrated. If you're buying them for midrange gaming PC's, do what wererabbit suggested, and buy 2 4670's instead. They should cost equal or less but have a lot more performance than that 2 gen old card
If you want a performer, get a single 4850 for $85. If you need two adequate cards, get two 4670s for $65 each, and probably one of them on rebate too (Newegg has it for $50 AR). So make that $50 + 65 = 115 if you needed two cards.