Chances are, if it's OEM, you will need to purchase those parts. Sometimes, the rails will come with the case. The screws are standard and can be purchased at any computer supply store. Samewith the cables, just make sure they match the HD (SATA or IDE). Ordering online, the shipping will be more than the parts.
Thanks for the responses. Here is my build so far:
antec p183 case (if this turns out to be a bad idea, I will get the cm 690)
core i7 920
asus p6t deluxe v2
EVGA GeForce GTX 285 1GB 512-bit GDDR3 PCI Express 2.0 x16 HDCP Ready
G.SKILL 6GB (3 x 2GB) 240-Pin DDR3 SDRAM 1600 (PC3 12800)
corsair tx 750w
2 Western Digital Caviar Black 640gb 7200 RPM SATA 3.0Gb OEM (not doing RAID)
don't have monitor picked out yet
don't have optical drive yet (want as quiet as possible)
windows vista home premium 64-bit OEM
Still need to also get:
quieter heatsink/fan for cpu
don't know what to do about fan on the 285
quieter fans for p183
anti-static wrist strap (know of good ones?)
I am glad the deluxe has the SATA cables.
Are there different kinds of rails and screws, such as ones that assist keeping the hard drive quieter? What am I looking for exactly?
If amazon sells the rails and screws, I have free shipping there.
There are different types of rails, screws and drive mounting methods. They vary by case, including tool-less cases that that don't use screws. Check your case choice and see what's in the accessory pack. For a premium case you should get everything you need.
Check the Asus P6T Deluxe v2, and your case choice to figure out what you get with them and if you'll need anything else.
If you're changing fans in your case make sure you're not sacrificing too much cooling for quietness. Test the stock setup for cooling and quietness. Make any changes you need and test again to see if how things run after the changes.