"New comers to the service will find the Home icon on their XMB once we activate it. You wont have to look for it, it will be easy to spot and will appear under PlayStation®Network. However, if you are online on your PS3 when we activate it you will need to restart your PS3 for it to appear. Watch these forums for news on when that is. It will work like Folding@Home in that the icon will be there and you'll download the service when you first select it.
http://community.eu.playstation.com/playstationeu/board/message?board.id=b_EN_PS3_Home&thread.id=58096&view=by_date_ascending&page=1