[taosaur]

A lot of people (including me at first) don't realize that CM7 doesn't automatically mount any storage when you plug in the USB. You need to go through notifications (expand the status bar upward, or hit the green-arrow-in-a-broken-circle button) to the USB screen and "Turn on USB transfer." If you're running CM7 from SD, it will then mount the system (not boot) partition as if it were internal storage and the remaining partition as "SDcard" (though technically both are on the SD card). I never bothered exploring whether you can get it to also mount the eMMC.

In ES File Manager, your default homescreen will be the storage partition of the SD, but if you click button in the upper left with the SD card icon, it will take you to the root directory where you'll find the folder "emmc."

My NC is running the latest stable CM7 from SD with dalingren's OC kernel @1.3Ghz. On the eMMC I have un-rooted stock 1.2 and ClockworkMod Recovery (that was quasi-accidental, but has come in handy). All of the details of how I got my build except the overclock are in the link in my sig.