Since this is the PowerPC Macs sub-forum, I assume, you have a PPC Mac (G4 or G5), thus use "Apple Partition Map" instead of "GUID" in the following tutorial.
After you successfully formatted the SSD, you can use CarbonCopyCloner or SuperDuper! (you might have to look here for PPC and Mac OS X 10.4 or 10.5 compatible versions) to clone the HDD's contents to the SSD and then boot from the SSD via System Preferences > Startup Disk.