editing AVCHD and iSight clips from iMAC

Hi,
I'm starting a project where the video's I record will be used for the following:
1) Online Courses that will have pictures and slides as part of the video that will need to be inserted.
2) You Tube Web links from myspace and other websites
3) To be archived into a library for future viewing of students.

I started recording with a Canon HG10 HD, wich records in AVCHD. I have been told that this will cause me problems downline because of a need for "massive hardware" and many apps do not support it. I have an iMAC with iMovie 08 which appears to easily upload the videos however I had one error that told me that one of the files had a problem and that I had to view the video to find it. (no thanks).
I understand that I can import/transfer video from iMovie to FCP. (Great!)

The iMac also came with an iSight built in camera. I like using this camera for some shots and would like to use this video as well in the above named purposes.

Question: Am I creating future problems in editing by capturing my video with these two camera's?

What kind of "massive hardware" is this person talking about that I will need to use this video?

Is iMovie sufficient editing software to do these kinds of basic applications?

When does an editor move fro iMovie to FCP? Would I be better off just getting better footage with a better camera and editing with FCP, or is it too much of a tool for my simple purpose?

Thanks for your support,
Arturo Celleri

Do you have any recommendations, knowing that I have an iMac to create all of this with FCP on it.

Arturo Celleri