Server Help

Please help.I am the only one who can connect to my minecraft server,I portforworded it with 2wire and I have triple checked and everything is done right i got my IP from http://www.whatismyip.com and my friends use it and they can't connect.Only i can connect. I use bukkit and use a windows 7 laptop.Please help i want a place were me and my friends can play minecraft.Once again please help!