I haven't seen anybody else post this but apologies if I've missed it. MS have announced that Flight will be a free download (no registration required) available in the Spring. http://www.microsoft.com/games/flight/#
The free bit will just be Hawaii but other add-ons (scenery and aircraft) will come to those who open a Microsoft Games LIVE account. The graphics look good and the PC specs look light. I don't seen any sign of a big jet
Don't read too much into Flight, and dont be too put off by what you may read elsewhere. At the moment it is very Arcade, and that will be an aspect of it, with a pro version which will be more in line with what we are used to with FS9/ FSX. The "pro" version is well over a year away yet. Please note there is no beta of the "pro" (or whatever it will actually be called) the only beta is this free(ish) arcade version. FSX will be arround for a good few years to come I'm sure.