Edit into rc.local:
modprobe ramzswap num_devices=1
rzscontrol /dev/ramzswap0 --init
swapon -p 0 /dev/ramzswap0
To grub also add a vmalloc= setting to match the ramzswap size.
This is the compcache vs disk swap test: http://code.google.com/p/compcache/wiki/Performance/SwapDiskVsRamz
P.S. If you have more than a gig of ram you probably want to set a manual compcache size of say 256M and vmalloc=256M setting to match since default is 25% of installed memory which is excessive at large amounts.
P.S. The more memory limited or low-end your machine is, the bigger effect compcache will have. Even on 4 core, 4GHz, 4G ram machines I run this though. Why torture yourself with swapping?
Swapping is so 1200's man, come on and enter the 14th century already!