So I have this great new phone, and I'd love to put some J2ME or similar software on it, and maybe even use its mini-USB to provide memory expansion. However, as we all know, most mobile phones come with a very restricted OS (to protect the carrier's business interests, hoping to up-sell with ringtones, etc. and seeing the phone as a contract to buy their service for two years), preventing JPEG transfers, any non-vCard data connectivity, etc.

I'd like to rewrite some of my phone's software as an interesting hacking project, in the hopes of providing expanded capabilities for my phone. Some of my other aims may not even require circumventing or overwriting software. I think that a Subversion browser would be great for viewing patches, recent activity, etc. out of the slow confines of the installed web browser.

Where are the best places to get your hands dirty programming phones? I'm interested in both low-level and high-level modifications and development. I have high-level programming experience with PHP, Python, and JavaScript. Basic knowledge of Java, Ruby, Erlang, and C.

Do you still want to be able to have service on it? I don't really know about programming phones, but it seems like you'd run into problems with some proprietary communications framework between the phone and the carrier. I know I had to program my phone via the cell network before I could even place calls, and that was with a phone already loaded with firmware from the carrier.
ta0kira

I'd like to start high-level, and get into the internals as necessary. You're right, there's a good chance that I'd have to overwrite parts of the system that handle the mobile service, which would be a show-stopper. I'm just trying to get a feel for the lay of the land, I guess.

Well, I am not posting any info about phreaking. But you could start of your research with an iphone. It has ssh! The best part for me that its a darwin and lots of stuff I know works on it.
Building a sniffer on a mobile would be something that I have been looking on. Could reveal hell lot of information.

I've also been interested in the past in programming cellphones, so anybody with any info, please post.
Webdevil: No please don't write a sniffer, and please don't do that with the info that people on here may give you, that'll just make them stop giving you (and in the process, the rest of us) the information that is so vital.

I'd just like to add that when I went to the gnu.org website the other day, they had a Banner saying that everyone should boycott the iPhone3G because it apparently disallows you to install your own (free, Open Source) software on it. So - don't use that one!

Exactly, I'll be more interested in Android when it comes out. But like I said, I'm interested in taking this very simple phone and coaxing additional features out of it. Stealing mobile service is not one such feature, so no worries about "phreaking".

I don't think that would be phreaking, anyway. I'm sure very few people do real phreaking still, which involved directly-connected hardware designed to manipulate the phone-line infrastructure to exploit hardware-based weaknesses. Everything is software now, or is at least filtered and electronically isolated, so "cracking" would be the more appropriate term. You can't "phreak" from a cell phone, regardless.
ta0kira