I'm running Slack 9.1 with the 2.6.6 kernel. I'm trying to set up LVM. I have tried both the lvm-1.07 that comes with 9.1 and 1.08 that lives in slack-current. With both of these running vgscan dies saying that the LVM module is not loaded or is not included with the kernel. I know that in the 2.4 kernels the lvm module was called lvm-mod, this seems to have changed in 2.6. I have tried turning on everything in the drivers/RAID-LVM section of the kernel, both as a module and as included in the kernel. I'm guessing that I need to recompile LVM itself with the 2.6 kernel. I just wanted to see if anyone else had done this already.

this may explain

http://tldp.org/HOWTO/LVM-HOWTO/whatislvm.html

looks like you need lvm 2. hope that helps.
good luck.

LVM2 is what I needed, just should have read more before I posted. After installing lvm2-2.00.26 and device-mapper-1.00.17 everything works fine!

Even though device-mapper core is in 2.6 now, you still have to create the library from source, lvm2 looks for it during make.