I've got some action sequence style photos - A bike rider doing a jump, and want to combing the 3 in the one photo.

I have lightroom on my computer, and have access to CS5 on a friends.

I can do an ok job of it in photoshop, Lassooing the section of each image, putting it overtop in a new layer and making it slightly transparent. I didn't shoot this off a tri-pod and as a result each image is slightly shifted to the last.

Is there an automatic script that can sort this out for me, or am I spending a bit of time getting it right?

Thanks.