1)can anyone please tell me how to connect my laptop running hardy to
a friends laptop running windows
2)also i need information about lan settings(wired) as we have a lan network connecting all 500 computers in the hostel.i just cannot figure out how to connect.in windows my friends use lanscan software.is there a similar one for hardy?

There should be a network configuration tool under the system menu in ubuntu.

If you are connecting to a friends laptop without a router in between, you will need to use static IPs. Set one computer to 192.168.0.1 and the other to 192.168.0.2. The subnet should probably be 255.255.255.0 on both.

If you are connecting to a large network with a router (like a hotel), you should just be able to use DHCP to connect. There is a box you can check to do this.

Not sure what lanscan is, but there are plenty of linux network mapping tools like nmap.