There is a well known deficiency in the Windows Server 2008 backup utility that does not allow you to easily back up Exchange 2007, the way you could with NtBackup in 2k3. The Exchange team promised a solution but never provided one.
What are some (hopefully cheap) options?
Exchange 2007 SP2 has now provided addon support for the Windows 2008 Server Backup tool.
Great Question Eric. I have been looking for a solution myself. Here is what I have found so far. Each looks like it has its own advantages/disadvantages. I haven't used any of the them yet..
Commercial/Paid Software:
Free Script: - MBS-online-backup.ps1 (GUI Version) - Uses powershell and VSS to make an online backup. I have tested it out and it works pretty good. There aren't any recovery instructions posted yet though but I think you can mount the backup files as a recovery storage group. Not for the faint of heart but looks like it will get the job done.
See my answer to the related question - ntbackup.exe, Powershell, ExMerge, or offline backup.
Good news: the solution is coming in Exchange 2007 SP2, coming soon. See this article for full details. In the meantime, I'd use the MBS-online script that @TonyB mentioned. Michael B. Smith, its author, is a very knowledgeable guy, and his script does a good job.
Microsofts DPM seems to be the common choice with many.
There is also an article here that seems to indicate it is possible to backup Exchange using NTBackup on server 2008 with some hacking. Not sure how well it restores though so you would need to test that quite thoroughly.
The problem with using NTBackup is that it can corrupt the mail store if you have LCR enabled. Not sure sure what happens with SCR enabled. Without either of these enabled, NTBackup should run through fine however it will be necessary to test after major updates.