After many months of unofficial CM7 ports, LG Optimus One has finally received official CyanogenMod support. The nightly builds of CM 7.2 for LG P500 are now available on CM mirrors.
At present the nightly builds are a bit buggy but they are improving with every build, almost 1 new build per day. 
Once the bugs are ironed out, a stable release will be made.
Download the nightly builds of CM7 for LG Optimus One P500 here.
How to Install CyanogenMod 7.2 on LG Optimus One P500
P.S. – The official CM7 builds are for the new baseband only.