I spend loads of time chatting on MSN.

• To spend time: this means to pass time. E.g. I work from 9.00 to 5.00. I spend eight hours at work.
• Spend loads of time… loads of is a colloquial, informal way of saying lots of time.
• To chat means to talk (informally / casually) with someone.
• Chatting. There are lots of different 'chat rooms' on the Internet where you can 'talk' to people (that is, chat with people) by typing messages to them.
• MSN provides just one chat-room service out of many.