I'm writing a bitcoin app and would like to validate addresses somehow.  I found this regex for public addresses:

/^[13n][1-9A-Za-z][^OIl]{20,40}/

But I'm looking for one for base 58 private keys as well.  (Base 58 is the import format right?)

I don't know a lot about the rules for these keys/addresses.  If I did I'd just write the regexes myself.  Any help is much appreciated.