Encryption in Sql 2000

I want to encrypt my site user passwords which r stored in a table Login so that when anyone wants to see the passwords he will see only encrypted not the actual one.But the admin can see the actual passwords by some means.I am using Sql server 2000and ASP as the programming language and my site is situated at VSNL india.So pls give me some solution for encryption and decryption also??

regards
pankaj