How to set up Ubuntu as wireless accesspoint?

How can I set up my WiFi to be used as wireless access point on Ubuntu Server?

I have a local Ubuntu Server, it has a wireless card in it (802.11a/b/g/n) and I really want to set it up as an 802.11n access point since my normal access point does not support N.

It needs to work as a switch as well so I can connect and get DHPC through.

Edit: I don't see Network Manager as a good solution since it depends on a lot of X11 packages, and i don't want that on a server.

I found a good thread. It should work in Ubuntu 10.04 no problem. Also it is CLI so it doesn't need any X libs at all. :)

Click on your NetworkManager icon in the panel, and choose "Create Wireless network..." You should be able to set this up as a "System" (as opposed to "User") connection.

You say that this is on a server, so perhaps you're accessing the server through SSH only. In that case, you can try some remote X connection; or try to configure NetworkManager through the command line, which should be possible, if non-trivial.