Question : How do I transfer from SQL 2005 to SQL 2008 on a new server?

We have a SQL 2005 server with its databases on a SAN backend.  We have built up a new SQL 2008 server with the same name. Last night we edited the SAN zoning to the new server, joined it to the domain, and attached to the databases on the SAN.  I ran the script to pull the logins from the old server and add them into the new server however when we booted up application servers (BMC Remedy and ColumbiaSoft Document Locator and others) they are unable to access the backend databases.  

If the same databases are attached to the new server (running in 2005 mode on the 2008 server), and the logins were ported over, what else am I missing?

Since the company was down for over four hours, we reverted back to the old server to put the company back online while we research this further.  Is there a preferred method of migrating to a new SQL server?  If possible, I'd like to keep the same server names between the servers so I don't need to reconfigure the application servers and keep the migration transparent to the users.

Thanks,

Answer : How do I transfer from SQL 2005 to SQL 2008 on a new server?

If you want to keep the same server name, you could instead create an alias in DNS -
Build the new Server, give it a new unique server name, get everything setup, move across the databases, sql jobs etc from the old server. Then create an alias with the same name as old server. Shutdown the old server and now users who used to point at that will be pointing at the alias and getting to the new server instead.