To compliment my MOSS certifications, I’ve recently sat and completed both the 70-667 (TS: Microsoft SharePoint 2010, Configuring) and 70-668 (PRO: Microsoft SharePoint 2010, Administrator). While there are no official study guides available at the moment, I can strongly recommend Wrox’s Professional SharePoint 2010 Administration paperback as a great reference and study guide to compliment your real world experience.
As far as tips are concerned, I’m not allowed to mention any specifics relating to the exams, but make sure you check out the skills measured sections at Microsoft for both.
70-667 tests your technical abilities and knowledge of the product while 70-668 ensures you have the knowledge and skills to design, plan and implement a SharePoint 2010 environment. If you’re comfortable with everything listed in the skills section, you shouldn’t have too much of a problem.