Is there a way in TFS\'s reports that you can get the amount of time taken for a work item to transition between states?
Looking at the data in the Tfs_Warehou
Basically what you want is retrieve the ActivatedDate and ResolvedDate fields (or other date based ones) info for every bug then compute the timespan for each Work Item and do some per Work Item display or average. Am I right?
So, you have fields in the OLAP Cube for ActivatedDate and ResolvedDate, the reportable type is set to Dimension, which means you can't do what you want with these fields because they can't be used as values in Excel (which is what you'd need to do the maths). To make the matter more complex it looks like you only have the date and not the time, which would be not precise enough for you.
In short: SSAS/Olap/SSRS won't help you in this case...
Well, SSRS could help you but you would have to develop an TFS warehouse adaptor to inject the data you want in the TFS Warehouse: good luck with that! (it can be done, but the first time will be painful).
If you really need this info:
You can write a little program that will use the TFS API to make a Work Item Query then get the value of the fields you want and develop the logic you want. It can be an excel add-in if you want to populate a grid and generate a graph from it.
If you're interested in TFS and plan to keeping working with it: it's worth the investment thousand times. Writing apps is easy and the good thing is once you've made one you can easily tweak it for new needs.