Here’s a pretty good video regarding upgrading your MBP to having both an SSD and a Hard Drive. I just replaced my drives using pretty much the exact method shown in this video.
Make sure you put the SSD in the hard drive slot, and put the hard drive into the CDROM adapter. The reason for this is that the CDROM drive uses SATA II, and the HDD port uses SATA III, and your SSD is more likely to hit that theoretical speed peak.
Also, a word of warning, the accelerometer won’t set off the hard drive safety feature where the head goes back to a restful state. So, no more tossing your MBP around.
Also, you will need a Torx T6 screwdriver, a tiny philips (buy a kit on amazon for $15, or buy them from your local Lowes), and you’ll want to download the Lion install disk. No USB drive needed if you do it right.