Getting Ip's:--

To see the ip all computers you are connected to (web servers, people attempting to hack into your computer).
Go to dos (start>run>type command) and run the netstat command. Type netstat /? for details.

Type netstat -r at the command prompt to see the ip of all computers you are connected to

In MSN (and other programs) when you are chatting to someone everything you type goes through the MSN servers first (they act as a proxy) so you see their ip rather than who you are chatting to. You can get round this by sending them a file as MSN doesn't send file through its proxy.
When you type the netstat -r (or -a for a different view) the ip's are under the foreign address table. The ports are seperated by a : . Different programs use different ports, so you can work out which ip's are from which program.