Don't forget to check out www.clove.co.uk for more content!
UPDATE: Some USB mice are now reported to be working! Will update soon with more information!
Demo of USB OTG in Samsung's Galaxy S2 - seems generic USB OTG cables will work (mine came from here: http://tiny.cc/os3s1 ), so no need to wait for Samsung's overpriced ones. Quick demo of bluetooth keyboard and mouse connections also. Video recorded on a Samsung Galaxy S, using a Nokia DT-22 attachment to connect to a Gorillapod. Two video segments edited together using the 'Video Maker' app onboard the SGSII. Unfortunately despite using a tripod there is a bit of shake from whenever I leant against the table.
EDIT: I wonder if the one dislike on here is from GSMarena, because I beat them to this! ;p