Can't access IIS8 from outside

I have set up IIS 8 on W7 and can access a site I created from the host machine using "localhost". However, I cannot access it from outside using the IP address, viz:http://<IP address\MySite\Default.aspx

I know the IP is exposed (I have XP on gthe same machine in a dual-boot arrangement and IIS 5.1 is accessible when that is the OS in use.

I know that the path is correct as the path I use internally is:

http://localhost\MySite\Default.aspx

It is some kind of configuration issue but I can't find exactly what in IIS manager.

Many thanks.