I wanted to have a go at converting a bunch of photos i've taken over the last few day into a really fast video. It took me a while to work out the settings, but here's what I ended up with:

ffmpeg.exe -f image2 -r 4 -i %5d.jpg -vcodec mpeg4 -s 640x427 -r 30 -q:v 3 test.mp4

Explanation:
-f image2
means use the image convert
-r 4
means 4 fps
-i %5d.jpg
means all the files are in sequence like 00001.jpg etc
-vcodec
means use mpeg4 codec
-s 640x427
is the frame dimensions
-r 30  
I think this is the final frame rate
-q:v 3
means use high quality variable bitrate
test.mp4
output filename

Worked a treat. Next step is to add in some sound!