Yes, it is already working for vanitygen. It seems to be not working in oclvanitygen (I found this thread searching about that.)
Example litecoin litecoin addr: vanitygen -L LiTe . Namecoin: vanitygen -N NC . Any other coin can be done with the -X flag that lets you specify a version code (though it may be a bit of work figuring out what your coin's version number is.)
Actually it is not that hard.
![Wink](https://bitcointalk.org/Smileys/default/wink.gif)
Just go to the source files and look at the Base58.h file.
Around line 280 on most coins, look for the constant PUBKEY_ADDRESS being assigned. That would be the address version you need.