I am looking to experiment with J2ME for one or more Java enabled phones. Currently, I have a Nextel i730 (love Nextel, but do not like the i730) and am considering a switch, perhaps to a J2ME capable Sanyo on Sprint. While I know there are toolkits to write apps against, I know (not specifically) that some phones have adapters that allow connection to a PC while others do not. Have you found a particular phone/service/resolution to be best for development? What method do you use to test your code on your actual phone after doing so within an emulator (or do you perform this process in some other way?)
If you get a phone with infrared or bluetooth, you can connect to your PC that way (and the new phone will usually come with a CD or you can download any required software of the phone manufacturer's web site). What I do is put my midlets on a server and just download them via wap. It's a lot easier and - in the case of older phones that don't have infrared or bluetooth - a lot cheaper than buying cables.
So then it's just a case of: get the midlet working on the emulator; upload the midlet to the server; download it to phone via wap; then give it a real test.
If you are thinking about Sprint, make sure you get one of the newer MIDP 2.0 phones. You'll need to install your apps over the air for testing but there are lots of tools around that make that pretty easy. I offer one at my website.
Not many Sprint phones will install MIDlets over a cable. The Treo's will do this. There's a program called BitPim that will install MIDlets on some Sanyo phones. The LG-325 has Bluetooth but you can't push MIDlets to it.
Personally, I think Sprint is the best US carrier for hobbists. There's poor developer support but you can at least install applications without begging for Nextel's permission.
For people who are actually trying to make money, use Verizon's BREW system instead. You'll never sell much on Sprint.