Make sure it's really what you want to do. I don't think you need to worry about him getting more attached or it getting harder to wean. It sounds like he's plenty attached now. You can check out Kellymom.com for good info on extended breastfeeding if you are considering continuing.
If you do decide to wean I would try to cut back very gently. Choose the best feed to drop first. I would think either the early morning/middle of night feed. I would keep nursing at naps and bed for awhile. Maybe each week try to drop one nursing session.
Try distraction when you say no to a feed. Tell him when you will nurse him. (ie: upon waking, "we'll nurse before nap, lets go get breakfast now" Then make sure you have a fun breakfast, something he really likes. Or at night: "mommy will nurse you when the sun wakes up, let's rock in the rocking chair".)
When I weaned my first off the night feed, she had to throw a huge fit and see that I wouldn't give in. I was trying to comfort her in other ways then nursing and she just wouldn't have it, so I put her on the ground and said okay have your fit. She threw a fit for awhile, and then would let me comfort her. She did start sleeping longer.
Then much later when I was ready to wean her, we dropped feedings until we were down to the bedtime nursing. I started to limit the length of the feeding. I would do one minute (for w few days or a week - I can't remember), then 30 seconds, then 20, then 10, eventually we were down to one second. I know it sounds funny, but it helped her. One night my husband was putting her down (I was out) and she wanted to nurse. He said lets pretend and let her pretend to through his shirt. (Just basically turning her head towards his chect and him counting to one. ) After that we gave up the feeding. She was about 2.
Sorry to ramble, I hope this makes sense. I'm trying to rush with my 4, 2, and 8 months old in the background. Email me if you want more info.
C.