So, you've decided to ignore my advice and brave the crowds, eh? Fair enough. Here's what you'll need to know-and bring with you-if you're hoping to snag an iPhone 3G on launch day.

Note: This survival guide is for U.S. iPhone buyers only; for everyone else, check with your local iPhone carrier.

Do your homework
Before you trek out to the Apple or AT&T store of your choice, do everyone a favor and decide on an iPhone 3G model and rate plan ahead of time. Sure, you'll be free to hem and haw at the store, but it'll speed up the process for you-and for everyone in line behind you-if your mind's already made up. AT&T has an "iReady" PDF that outlines all the available iPhone 3G models and calling, text, and data plans, as well as extra fees (such as activation and upgrade charges). Download it and study up.

Prep your iPhone data
Already own the 2.5G iPhone? Sync it one last time before you head out. Also, if you have any unchecked voicemails, check 'em now; they'll be deleted the moment AT&T activates your new iPhone.

Where to go
The iPhone 3G will be available at any Apple or AT&T store. Reps for Apple and AT&T say the buying experience will be roughly the same at either store. During last year's launch, however, AT&T locations ran out of stock much more quickly than Apple retail stores (many of which didn't run out of iPhones until long after the initial launch). So if you're worried about the iPhone 3G selling out, an Apple store is probably your best bet.

That said, here's an important caveat: If you're buying the iPhone 3G under a business account, you must go to an AT&T store; Apple clerks won't be able to handle that type of transaction.

When to go
Both Apple and AT&T stores are slated to open at 8 a.m. sharp (local time), and orders will be processed on a first-come, first-served basis-no pre-orders or waiting lists. As of Wednesday morning, only a handful of publicity hounds in NYC and some die-hards in Japan were camped out in line. However, as the appointed hour approaches, lines could well snake around the block at high-profile Apple stores, and we'll also see smaller (but still significant) lines at AT&T locations.

Since AT&T stores might sell out earlier than Apple stores (if last year is any guide), you should probably go to your local AT&T outlet nice and early. If you're going to a high-profile location, consider arriving at least an hour or so before the doors open. Lines will probably be shorter than at Apple stores (especially at out-of-the-way AT&T locations), but you'll stand a better chance of getting the exact iPhone 3G model you want if you're there bright and early.

Going to an Apple Store instead? Since they're unlikely to run out of phones and the buying process looks to be pretty orderly (see below), I'd suggest going in the early afternoon, after the morning crowds have (hopefully) thinned out and before the 5 p.m. evening rush.

What to bring
You'll need a credit card and a valid, government-issued photo ID. Also, if you're a new AT&T customer, bring your social security number (for a credit check), plus your existing wireless account number and password/PIN-or, even better, just bring your most recent wireless bill. Already have the original iPhone? Bring it along; it may come in handy if clerks have trouble pinpointing your account. At the very least, it'll help you pass the time while you wait.

What to expect
Here's what we know about buying process at Apple Stores: Once doors open, customers will be admitted 30 at a time, and once inside, you'll be greeted by an orange-shirted "concierge" who will herd you to the "iPhone bay." Next, an Apple specialist will help you pick an iPhone model, decide on a rate plan, and activate your new iPhone. According to AppleInsider, Apple clerks will be armed with wireless EasyPay handhelds that'll let them process your transaction and activate your iPhone 3G on the spot. Apple execs say they hope each transaction will take 10 to 15 minutes, good for "processing" about 100 customers an hour.

Details about the buying process at AT&T stores are somewhat sketchier, although AT&T reps say it'll be more or less identical to the Apple Store experience, with transactions also taking about 10 to 15 minutes.

How much will I pay?
Check out my post last week for pricing policies for the iPhone 3G. In a nutshell, new AT&T customers and anyone who bought an iPhone before July 11 are automatically qualified for the discounted $199/$299 iPhone 3G price. If you're an existing AT&T subscriber but don't own an iPhone, you'll need to see if you're eligible for the discounted iPhone 3G price (log in to your AT&T account to find out). If you're not, you'll pay $399 for the 8GB iPhone 3G or $499 for the 16GB model.

Individual and family rate plans are detailed in AT&T's iReady checklist.

Also, keep in mind that new AT&T customers must pay a $36 activation fee, while existing customers must pony up an $18 "upgrade" fee.

What'll happen to my old iPhone?
Once your new iPhone 3G is activated, you won't be able to make calls on your old iPhone anymore. However, it'll still work as a Wi-Fi iPod, and you'll be free to sell it or hand it off to a friend (watch this video for details).

Anyway, to those of you looking to brave the crowds, good luck. I salute you.

Still have questions? Post 'em below.