Whilst I don’t yet have certification for 70-178 (2010) – yet, I am certified for 70-632 (2007).
The Certification remains current for as long as the software is supported by Microsoft. So, even though 2010 is in use now, previous certification in 2007 is still relevant as Microsoft still supports Project 2007.
It is obviously a good idea to keep our certifications up to date though, and I would recommend certification if your office is using 2010.
Searching for training at microsoft.com will give you information on how you should prepare, there are many options so you should be able to find one that suits your needs.