There's a cover that easy to remove to see the belt. Look for fraying/cracking, make sure it's not loose, etc., however I've heard that just because the belt is in good shape, it doesn't mean it can't go soon, especially if the tensioner fails catastrophically. I don't think it's easy to see the tensioner with the cover off, and don't know how easy it is to tell its condition just from inspection anyway.
If the timing belt breaks you'll end up with bent valves, which might constitute ruining the engine, depending how you look at it. It's ruined enough that a used replacement engine can cost less.
No it's not an easy job, but doable if you're somewhat handy, a little brave, and have a whole weekend to devote it if needed. Check out DaddyMatt's article in the info section on clubB5.com for lots of details.
edit: Oh, and the part about the 40k service that matters for this subject is the inspection of the belt which you'd want documented if you were to make a claim on the 10/100 PT warranty.
Modified by passatcabrio at 10:45 AM 7-6-2004