Slide show with video

Okay, I tried searching previous threads and didn’t find quite what I’m looking for. Basically I have to create a slide show that may contain say 100 slides. The project will also contain 5 videos ranging in size of 50 to 100 megs each. Each slide will need to have the ability to move the playhead to a certain point in a video. I guess this can be done in flash, doesn’t seem too difficult, but should it be done in flash. People at work are trying to push this one on me, thus the suggestion to do it in flash, because they are too scared to try it. I am willing to learn any other dev studio that may be better for this type of project. One more note, this must be viewable accross both PC and MAC platforms. Any suggestions would be helpful. I’m just trying to start on the correct path.