I want to make some rose petals appear to fall and blow in the wind for a short logo sequence (10 seconds) what the best way of doing this in AE?. photo attached of the basic idea. Any suggestions appreciated.

Keyframes. You'll basically need to save each pedal as it's own file from Photoshop & work with one at a time. Use Scale to keep them big at the top, then small as they fall and change the position across the screen from the beginning to end so they don't fall straight down.. There's a way to rotate them as they fall/get smaller, try clicking in the pedals name in the timeline, and try click 'R' for rotation, I beleive that should work. There should be a field for # of rotations thru the duration, this causes them to spin as they fall. Probably only need to set it at 2 or 3.

If you have AE 7 or later, I think you can make it fall in 3D as well. (Basically, make it spin as well as flip head over heels). I believe you do this in by clicking Layer-> then something like 3d view. Not fully sure but the rotation should work well enough.

Hope this helps, at least a little.