Difference between MD5 and SHA

MD5: 128-bit/16-byte digest. Somewhat faster than SHA.
SHA: 160-bit/20-byte digest. More secure because stronger against brute force attacks.

MD5 was developed by Professor Rivest (1994).
SHA (actually SHA-1) was developed by NIST (1994).

Links:

MD5 Homepage (unofficial)
SECURE HASH STANDARD
The Secure Hash Algorithm Directory MD5, SHA-1 and HMAC Resources