Not supported, you will have issues.
https://kb.altiris.com/article.asp?article=46349&p=1

Wait for SMP 7.1 to be released; this will include support for Server 2008 including Server 2008 64-bit.

If you need to move forward with Altiris 7 now, but can't wait for 7.1, and really prefer 2008, install on 2003 with the database on a dedicated SQL server (preferably SQL  2008 64-bit).  When the time comes to create that 2008 box for 7.1, the migration will be easier with your database off-box.

Does this answer your question?

So you can use SQL 2008? That is great. I am using SQL 2005 off box now but want to upgrade to 2008. Is there anything I need to do when it comes to migrating the data?

Everything but SQL 2008 R2 is supported in the current release.

I have been hearing that NS7.1 will REQUIRE Server 2008 64-bit.  Does anyone know if this is accurate?

This was discussed as an idea, but there is no evidence that this is being developed.  I doubt they would do this.  It is on Connect forums as a "what if" conversation.

ITMS 7.1 (incl. CMS, SMS, AMS, and ServiceDesk) will be 64-bit ONLY.  The supported operating system will be Server 2008 R2.

It's not the first time I've been wrong.  Oh well, 64-bit only isn't that crazy.  Same as the "NO FLOPPY DRIVE!?" mania.

What about running this on a VM. This 64bit stuff is going out of hand. I don't mind running SQL on a physical box and ITMS on VMs. Any info on that?

https://kb.altiris.com/article.asp?article=46349&p=1

ESX 3.5 and 4.0 are supported.  Hyper-V may work, but no guarantees and not supported.  Others are try at your own risk.  Make sure to meet hardware specifications by assigning as many processors, as much RAM, and fast enough disk as if you were building a physical server.

We all can't still live in the days where our infrastructure is running on Server 2000 with SQL 2000. Wake up, everything is 64bit now and will be that way for sometime until 128-bit computing comes out. It's like IPv6. Everyone wants to complain that they are being forced to move to something when it has been around for almost 10 years now.

Server 2003 64-bit has been out since 2005. If you are too lazy to deploy 64-bit servers or don't have the hardware then it is time to get into the 21st centruy and upgrade those 10/100 switches, Windows XP machines, and 32-bit servers to 64-bit. The next client release of Windows is 64 bit only, and the current release of Server 2008 R2 is 64-bit only.