Swoop,
Theres several sites that allow for free downloads after you pay a yearly membership fee. Others let you download but at reduced speeds.
www.simviation.com - good library that was NOT down when avsim was hacked earlier last year. Lots of birds and addons.
www.avsim.com - considered by many as the mother of all download sites for any version of MSFS
www.flightsim.comwww.flyawaysimulation.comwww.sim-outhouse.comwww.surclaro.comCheck out
www.vatsim.com if your looking to fly with live ATC. This makes the flights interesting at the very least.
There are also a bunch of groups that fly together. Im in one now that is currently flying an around the world flight in the Grumman Goose, flies sailplanes, and is working on missions that follow flightplans used for the Dambusters Raid, Operation Chowhound, and ferry flights to the various theaters of the war.
Payware aircraft are GREAT but be sure and check around the forums on the sites above before spending your money.
Let me know if I can help out!