I decided to take the plunge this morning and get OS2008 on my N800. I'm running a fresh install of Ubuntu Gutsy, and start the process.
Once I run the flasher program, it stays at the "Suitable USB device not found, waiting" line. Any tricks on how to get it to recognize my N800 (as it sits there with a little USB icon in the corner, obviously connected)?

you need to hold the home button while powering up the tablet

I've been doing that. I get the tablet onto the Nokia screen with the USB icon in the corner. I don't see what I'm doing wrong

I had this trouble too, till I figured which one is the 'home' button.

It's the bottom half of the three-way button, has the icon that looks like a house

When you get it right, the device will remain on the white screen with the usb icon visible.

Try restarting Linux, may be the USB driver / port got locked somehow.
Or try changing the USB port.

If you get the USB connector on the top right corner, you're probably already hitting the right home button (to answer Greyghost).

Still no luck on it. I've rebooted and changed the USB port a few times. Flasher doesn't recognize anything, and the N800 is definitely in the required mode.

What's the command you're executing ?

./flasher-3.0 --enable-rd-mode

What modules are loaded (listable with lsmod and/or usbmodules)? Does the computer recognize any other USB devices on that connector, mass storage (like USB sticks, card drives) in particular?

Does plugging the N800 generate messages in dmesg, and what does udevmonitor print if you plug it in?

And in case you missed that: You are running flasher as root or from an account with unrestricted access to that USB device?

Sevo

When I do lsmod, the tablet doesn't show up, no matter what port it's in. My flashdrive and Bluetooth adapter show up no matter what ports they're on, though.