Johnathan Kehayias has published something very much at the forefront of my thoughts right now, an article entitled How do you learn BI as a DBA?
Having earned my MCITP Database Administrator 2008 and MCITP Database Developer 2008 last year, I'm keen both to certify in BI , expand my SSIS development work and get to grips with SSAS development.
The following articles are referenced in Jonathan's post and will serve as my starting point too.
Planning Your First Microsoft BI Solution
Building a Data Foundation for a BI Solution
Building Your First Cube