Nokia Series 40 and Series 60 Reset Codes:

Full Reset: (clears everything off the phone memory!! Be sure to back up your contacts!!): *#7370#, 12345 and then Yes.

Soft Reset: *#7780#, 12345 and then Yes. (Also works on Nokia S40 phones, NOTE: On the 6230/6230b, same as going to the Factory Reset option under Settings!! Thanks to Tris for the headsup!!)

*#335738#
*#delset#

This deletes the Email, GPRS, MMS settings that cannot be erased via phone options. (Series 40 phones only)