Should I email a potential employer telling them I am still interested, but another opportunity is devolping?

I had an interview two weeks ago for a job I really want. They haven't contacted me yet either way (they said it would be two weeks or more) but another opportunity is coming full circle and they will be offering me a job next week (a "second interview/orientation"...sort of weird i know). So I want to email the first opportunity and tell them that basically I need a response from them so I can decide what to do here. How should I word it, or should I not even tell them??