Exchange 2007 (and 2010) rely on DNS for certain functionality more than Exchange 2003 did. Particularly, I mean the autodiscover record.
A great example is the out of office assistant. This will not work on your Exchange 2007 box unless you have your autodiscover information set properly.
There are a couple ways to do set it up, but I'll cover what seems to be the easiest and least costly way - the SRV record.
Some nameservers support SRV records, and some don't (it's different from an A, MX, or CNAME record) - which is where it can get weird, but presuming you have a nameserver that does, you can set up an SRV record with these properties:
Port Number: 443
Once that record propagates, your autodiscover will work properly (because SBS autocreates the appropriate information at remote.yourdomain.com/autodiscover)
There are other options like getting an SSL certificate that encompasses autodiscover.domain_name.com - but that requries more cost and isn't really necessary.
If you can create the SRV record with your nameserver, that's the best method in my opinion.
If you'd like to check on the status of an SRV record, you can follow these instructions or use Microsoft's site at https://www.testexchangeconnectivity.com
Hopefully, this will help someone. As I was investigating why my out of office assistant wasn't working, I feel like all the resources available to me were pretty vague about what was needed and how to go about it.
A good tutorial from Susan Bradley is here (which includes screen shots of setting up an SRV record on godaddy's DNS).