After talking with Verizon Wireless again (and more endless transferring from person to person), I came away with the following information:

• Their customer service department cannot find anyone capable of answering the question of whether or not I can tether a Bluetooth PDA to one of their Bluetooth phones for use as a cellular modem.
• They cannot even tell me whether or not they're still crippling the DUN (Dial-Up Networking) capability on their Bluetooth phones.
• Even if they could do so, their lowest-cost plan with both voice and broadband data would cost me $50 more per month than the equivalent T-Mobile plan.
• Verizon's plan does not include free use of any wireless access points, such as the ones T-Mobile has set up in pretty much every Starbucks in existence.
• Parts of their "unlimited" Internet service cost an additional charge of 25¢ per minute. (I'll bet there's no limit!)

Since one year of the higher price would actually end up costing $100 more than just paying T-Mobile's deposit (which, in theory, I will someday get back), I decided to bite the bullet and go with T-Mobile.

As it turned out, they didn't charge me the deposit. Hooray! After reading reviews of the Razr, I decided to go with a different phone, the Motorola V360. I like it so far; nice and light, it's got a decent camera built in, I can transfer MP3s to it for use as ringtones, and it'll charge off a standard USB cable.

The best thing, of course, is that now I can get my Nokia 770 onto the Internet even if there aren't any open wireless access points around. The speed's about halfway between 56K dialup and ISDN; not blazingly fast, but certainly good enough for basic Web browsing.