Hi,

I would like to connect to my friends laptop from my own using a cross network cable. Does anyone know how to do this, or has a link to a howto?
We are both running debian...

Manually setup an IP using ifconfig i.e.
yours:
ifconfig eth0 192.168.0.1 netmask 255.255.255.0 up

laptop:
ifconfig eth0 192.168.0.2 netmask 255.255.255.0 up

Your connected, now what do you want to do?

know how to transfer files, please

I would say FTP might be the easiest method.
Start the server on either PC and then connect with a client on the other.
Unless you configure the FTP server for anonymous connections you would to create another user on the server PC.

Don't know much about Deb, but in many linux distro's an ssh daemon is configured during install. If that is true for one or both of your boxes then just type sftp <insert ip addy here> and login. Obviously you'll need an account name and password to login to. Some systems allow root and some don't by default.

sftp works the same as ftp (get, put, etc) but you don't have to set up an ftp server if sshd is running on the remote box (other end of the crossover)... and has the side benifit of being encrypted but over a crossover that's not a concern. I only mention sftp because it is easier than setting up an ftp server if sshd is already in place.

-b