www.duat.com is pretty good.NB: Kindly don't file if you are not flying for real.

As Bob has said, the ADDS site is great for weather planning.When I want to quickly find the optimum level of flight, I combine AS2004.5 with FSBuild2. You create a saved wx file using the current data from AS2004.5, then use FSbuild to read it and give you wind components along your route. It's quite simple once you have your route planned. You just adjust the flight level, recalculate and read the resulting fuel burn, avg ground speed, and time.Bruce