Don't download it off co.uk.
It's made by Microsoft & it's a "WINDOWS LIVE" product, so the correct page would be:
http://ideas.live.com/
And it's BETA so it should be very clear that it has MANY BUGS! It was built off the original Windows Messenger system (NOT MSN Messenger), MSN has take some stuff out of their messenger and is now working together (they used to design it for microsoft) with microsoft's developers to create a better messenger.
So once again, it has many bugs. I do NOT recommend download, unless you are just trying it out. It isn't made for day-to-day use.