You question is somewhat vague. You have a lot of different options in regards to setting this up.
Generically speaking, you’d need the following: 2 identical servers that can individually handle the application they if you are running active/passive. If you are running active/active licensing costs increase.
1 small SAN device such as a Dell Powervault. 2 HBA cards to connect to the PowerVault. 3 NICs in each server. 1 primary, 1 secondary, and 1 heartbeat.
SQL Server 2005 Standard edition will allow you to build a 2-node cluster.