We ask the question even though we think we know the answer: probably not!
Yes, the HTC Titan on AT&T "launched" today (see our first impressions video) but from our experience and yours, supply seems to be might-t tight on the mammoth phone. We had to hit three AT&T stores to get one. And we mean one. The phone we bought was the only HTC Titan within 30 miles of us and we're in Long Island (metro NYC). From Texas to Alabama to Eastern Virginia to Indiana, we've heard most stores don't have them in stock. Our local AT&T store told us they were expecting some tomorrow (Monday), which is plausible.
So why the hold up? It's clear HTC missed the BIG New York City launch a couple of weeks ago. Remember the six-story Windows Phone thing? Granted, the Titan was technically there (the unbranded international version). But the AT&T one clearly was missing and our hunch tells us that AT&T and Microsoft would have preferred to launch three phones on AT&T instead of just two (Focus S and Flash). That tells us that HTC is probably having trouble either meeting demand or fulfilling their order to AT&T--whatever the reason, it is clearly having an effect on supply.
Your best bet if you don't want to order online? Call your store, give them your name. Store reps will personally call you to make the sale, so if you let them know you're interested, they'll most likely give you a ring as soon as some arrive. We also hear that Microsoft Stores do have them in stock and available--so if you're near one, that's a safe bet.
In the meantime, feel free to vent in comments and let us know if you got one!
Missing Titan image credit: Nick S., taken in NYC