The BBC iplayer is based on flash 10 and thus I would expect bad performance , all the way through till Q1 of next year when the N900 gets flash 10.1
On 9 April 2008 the BBC iPlayer was made available to stream video content on the Wii video game console via the Internet Channel (only available to UK residents). This was enabled by a recoding of the iPlayer to use Flash 7 rather than Flash 9. However, the Autumn 2009 update to the WII internet channel has resulted in the iPlayer no longer working on updated consoles.