Well, if it works for BBC iPlayer it will probably work for other British channels too, although ITV Player and Channel 4 on Demand (4oD) may be the only ones worth bothering with, though. For what it is worth, here are the links for Channel 5 and for Dave. (Yes, we have a TV channel/network called Dave! The programming is almost all reruns of panel games and reality shows that were originally on the BBC or other channels, though.)
I think you do have to register before you can actually view stuff with all of those, but that in itself should not be a problem. ITV player, however, may ask you to enter your postcode, which may screw you up unless you know which which postcode your apparent IP address will be coming from. It may be worth figuring it out, however, especially if you like detective/ murder mystery shows, because ITV pretty much has that market sewn up in Britain, and has lots of good material: not as innovative or edgy as what you will sometimes find on the BBC or Channel 4, but good quality scripts and high production values. (I think some is put out out via BBC America in the USA, but it is really from ITV, and will not be found on BBC iPlayer.) Some of the stuff in ITV player you have to pay for (and perhaps you can do that from the USA anyway, without spoofing your location), but it is cheap and often worth it. Other shows are classified as “catch up” (shows that have recently been broadcast, often in rerun) and are free (but have ads) if the system thinks you are in the UK.
Channel 4 (which actually runs several broadcast channels now, as indeed, do BBC and ITV) has quite a lot of American programming, but also some good original programming of its own (as well as some utter crap, of course, but that is probably true of any TV network).