Got my latest phone from Carphone Warehouse and found the staff to be knowledgeable about the deals available and more than happy to jumpt through hoops to change to keep my number when I switched from o2 and had no issues juggling the data/calltime numbers around after I found a better deal on their website. Not had a problem with them - I appreciate that some people will have a poor time when dealing with companies like this, and that anyone else's MMV but they're always the comments you hear/read about, it's rare someone will pipe up on an internet forum praising a firm.
I... don't know. Might be able to coax a proper linux install on there. Maybe.
But no, this is just the default OS (Linux kernel + busybox + some graphical shit).
I think this is realistically the most 'recent' thing you can get on there, and even that needs a bit of fucking around: http://www.angstrom-distribution.org/