You will need to get an Icy Dock 2.5" to 3.5" drive adapter...
http://www.newegg.com/Product/Product.aspx?Item=N82E16817994064
Then you just drop your SSD into the adapter and mount that to your drive sled in the MP as if it was a regular hard drive.
If your X-25M doesn't come with the latest firmware (v8820) you can update it by downloading
Intel's tool, burning it to a CD and booting to it. The SSD you want to update needs to be in drive bay 2 (don't ask... but it won't update the firmware properly if the drive is in bay 1).
If you buy two drives and want to RAID0 them (recommended
😀), you can setup the RAID array when you run the Leopard Install using Disk Utility.
That's it.