So how do I make sure that the Certificates are Valid? And how do I make sure that the Device ID (Is that the same as a UDID?) is in the mobile provision file? especially if that page will still not load on the development site?

Agreed that Xcode is fast and easy, but only if you are the only one needing to view your app. Usually, when I create an app, it needs to be previewed by a team (myself, creative director, art director, project manager, and client), so diawi.com is a quick and easy way to get to everyone with one quick and easy link. I haven't tried iFunbox yet. I'll look into that one! thanks Ivan!