I think it would probable be best to get someone in to do it for you. For one thing there will be a lot of rubbish to get rid of afterwards. Most companies shred the waste as they go. Down side is that it would probably be quite expensive.
It's a lot of work. When I cut mine down I found the best way was to leave 2-3 feet of trunk attached to give you some leverage to help break the roots. If you have just a few then you could hire a chipper to break down some of the branches. This can take a while though. If you have a lot you might just be easier to hire a van to haul away the bits. Be prepared for a lot of trips to the local dump otherwise. Invite some friends round to help it's a big job.
i left 18 inches of mine still in the ground and just grew plants around them..i know it sounds lazy but you cant see them..as plants cover them..and they dont regrow..