Install Stanza and Dropbox on your iPad. Set up a free Dropbox account.
Upload the .CBR to your Dropbox folder from your computer.
Open it in Dropbox app on your iPad. Dropbox will say it can't display the file, never fear.
Do "Open in Stanza." (This takes a minute or two. It's still quicker than other methods.)
Yes, there are other ways to do it (copy through iTunes, use Stanza's server, etc) but this is quick and easy, even for non-geeks.