For those of you struggling with DUATS, try FltPlan.com Flight Planning for General Aviation. You don't need a licence/number etc, I don't think. Great site with all the info you need for planning a flight at no charge. Another favourite I use all the time is AirNav
The problem is that the AOPA online flight planner (a new version out shortly which is much improved
) integrates DUATS data so a DUATS account is highly desirable.
I agree, Airnav.com is a great resource, as is SkyVector.com