Putting the speech to one side, there are many other duties that the Best Man could be expected to do. These vary from wedding to wedding, but below is a list of some of the main duties you could be asked to do, and how to do them.
Toastmaster / Master Of Ceremonies
This is where you announce the specific parts of the wedding. For example, when the wedding couple enter the room for the wedding meal, you'll probably have to get everyone's attention (tapping on a glass with a spoon with do) and tell them "Ladies and Gentlemen, please stand for the Bride and Groom". It's quite common to also announce the cutting of the cake, and introduce the speakers for the wedding speeches (normally the Bride's Father first, then the Groom, then you).
Lord of the Rings
Keep them safe. You'll be asked to present them during the wedding ceremony and pass them to the official conducting the wedding. Make sure you can feel them in your pocket at all times. Some people keep hold of them in their hands right until they pass them over which is fine, but these can make them hot and sweaty - and a nightmare to get on fingers!
Signing the Wedding Licence
After the wedding ceremony, you may be asked to sign the wedding licence as a witness along with the Chief Bridesmaid. In a church ceremony this is often done away from the guests - in a civil ceremony you'll usually sign it in front of them.
Organising the Troops
Once you arrive at the wedding, you're in charge of making sure the Groom is not only dressed correctly, but also in the right place. If the wedding is in a church make sure the Groom is around for photographs outside the church on arrival, but then moved into the church to prevent him seeing the Bride's arrival. You'll join him at the front of the church once inside. Also, check the Ushers are okay - they'll be directing guests to their places for the ceremony.
"To the Reception..."
There may be people, presents and cars that all need to get from the wedding to the reception. As Best Man, you should make sure that people know where they're going, and that everything that needs to be, is on its way to the reception (Presents, Decorations etc).
During the wedding day make sure that the wedding photographers or videographers have everything they need. In setting up group shots, they may need your help to get people into place - and they'll certainly need you for some shots with the Groom.
Presents and Gifts
You should arrange to have any presents moved somewhere safe after the wedding and then arrange for the delivery of them to the couples home. You should also take care of any keys, tickets, or anything similar that the wedding couple will need later in the day.
Let your hair down and have fun!
Above all else, you should make sure that you enjoy the day! You may be slightly nervous, but remember that everyone is there to have a great day - as long as you relax and look after your duties, you'll have a fantastic time! Any Best Man will tell you that they were dreading the job - but when it arrived they loved every minute of it.