Yes, you can. But your N900 might not be fully functional. Do it at your risk.
Remember: This is just a developer preview. Expect random reboots and crashes!
Final release is not expected until October 2010.

Anyways, links to download the image for N900 (Please read the instructions and warnings very carefully!).
http://meego.com/downloads/releases/...eloper-preview
http://tablets-dev.nokia.com/meego-codedrop.php