Hi George,
I think, you are using a PDA phone for the first time. Never buy a costly phone from resale market, as the reseller doesn’t give you a warranty of that phone. Better to buy a new brand phone that has at least one-year warranty.
Link to upgrade your TyTN from WM5 to WM6.
http://www.america.htc.com/support/8525/software-downloads.htm [america.htc.com]