(edit Zlatko beat me to it. :P

Let me tip you there, the pockatable computer you bought does not need a headset to make skype calls, as for the inbuilt microphone and speaker(s) will automatically do their job. Still, a headset will probably work too. You can also make a video call to pc's (at least under wifi) and other supported devices. Adding a contact in skype works via the contacts app, modify your contact and add the skype via the selection screen and type his/her usename. Deleting works the same.

As you see, skype as well as some othe services are well integrated into the Maemo5 interface. Assuming you are relatively new to it, welcome here