Are there any usability resources out there that specifically deal with the design of an analytics web application? I've been tasked to design a web app with a strong analytics component and I've been told there are different considerations than designing for "transactional" sites, but so far no one can point me to resources for reference.
Here is a collection of some design patterns for analytics on patterntap.
I would go into popular analytics applications and take notes like crazy.
I agree with your colleague: you'll want to look for application usability guidelines in general, as opposed to guidelines for transactional websites such as web shops.
Here's one for web applications - it's from 2002 and for flash applications, but much of the information also applies to today's rich web apps such as yours. Here's also a more recent list of common application design mistakes.