I just installed nVidia driver 295.59 on lucid. I have a partition with Precise 12.04 playing around with it to become familiar.
I don't think I would attempt to update the driver on 12.04 at least with these instructions.
But, if anyone is still on Lucid and wants to update, the driver just came out today June 11, 2012.
This is not for the timid. Read the first post carefully.