Ok, I assume you mean the Canon HFS100? That is an AVCHD camcorder that uses an SDHC card to record on - if you want to, you can store the footage for later importing - what you'd do, on the hard drive where you want to store the footage, create a folder named representing the footage your saving (ie: billy bobs wedding or whatever), then copy the private folder from the top level of the SDHC card into that new folder - not the contents of the private folder, drag the private folder over.
Now, in FCE and FCP, during log and transfer you can specify a folder to look for the AVCHD footage (in those cases, you'd point to the folder that was named for the event, not the private folder), I honestly don't know if iMovie supports that aspect (I almost never use iMovie), so to actually import it into iMovie, if you can't get iMovie to look at a folder, you would use a blank SDHC card and copy private folder back onto the SDHC card then import it into iMovie.
I'd suggest recording a short segment, import it into iMovie to check the footage, then follow the backup procedure, erase the card, then try importing the footage either from its new location, or by copying it back to the card. Although I have never had a problem handling footage this way, it's always best to do a test run prior to trying it with a lot of footage.
Hope that helps!