Neer help connecting to db in 11g

Ok, this is what I have done
I have virtualbox with a Windows XP pro as a virtual machine, I've installed Oracle 11g and setup a DB, and I can use Sql developer on it (the virtual os) but what Im tring to do next is use Sql developer on the host os, windows 7 Home premium, I can ping to the virtual os, but when I try to connect to the DB I get an error: The network adapter could not establisha a connection
Under :
Hostname I have put localhost and/or the IP of the virtual os
port : 1521
SID : utm (that the sid name Im using)

the listener service is running on windows xp (the virtual os)

Any help would be apreciated