The only encryptions worth using are one-way encryptions. C# has a few classes that can do this, the only one I have used is the System.Security.Cryptography.Rijndael class, however you should use AES instead if you need a more secure algorithm. There is lots of sample code on the MSDN website in the documentation for the System.Security.Cryptography namespaces.
no i dont think i will need to decrypt... i will save the decrypted format in the database and when someone logs in i will encrypt the password from the textbox and match it with the encrypted pass from the database. anyways i will keep this to for reference. thanks alot for your time.