It very much depends on the dongle. Are you using one of the mobile dongles - otherwise known as a mifi? This can act as a wireless hub.
If you have this you will need to look at the settings for the device which you should have on your pc - other pc's will need to have access to the IP address of your dongle - or you can set up ICS as described in the article below.
If you have just an ordinary dongle it is possible that you can get an adapter into which you just plug in your dongle and it will act as a wireless hub.
It may also be possible to share your connection using ICS - Internet Connection Sharing - see this article but I don't know how effective this will be.