I am looking into getting certified in SQL Server. Anyone have any good advice on where to start, what kind of books or training to acquire, etc?

It depends what path you want to go down; development or administration.

That said, I'd get a quality book and some good videos if you're home based. CBT nuggets do some good videos that train towards certification and the vids are reletively cheap
http://www.cbtnuggets.com/webapp/store?op=category&category_id=52

You may need a book for further detail.

You could go on a course or pay for an online course. It depends how well you adapt to the material, however, I personally don't think you need to spend so much money. If you need any help with problems, there are plenty of SQL server forums (incluing this site forum) that you can get help with.

Good luck

If I were to get certified in SQL Server 2008, would I be able to apply that to our current SQL Server 2005 databases?