This question of CRC routines has come up a few times in the past. This message is more for adding to the archive that people might search when looking for CRC routines but...
I uploaded some CRC routines to the Academy, including CRC8 and CRC16. Both are calculated versions right now, I'll add table driven later. Both CRC8 and CRC16 work with S.N.A.P. Lab (www.hth.com/snap), which is basically all the testing I have done on them. As well they produce the same results as BASCOM CRC8 and CRC16. The CRC16 is CRC-CCITT... later I will add CRC32 and table driven versions of CRC8 and CRC16.