This guide is copy - paste from Hopzone's forum .
And it was posted here in case to help people .
So the guide is here
1) Go to http://www.no-ip.com and sign up for an account
2) After you sign up, you will need to go to ur email and verify it.
3) After you click the link, a window will popup and say that your account is verifed.
4) Click on the Hosts/Redirects link on the "YOUR NO-IP" menu on the left.
5) Click "Add" on the menu on the left.
6) Under "Hostname" you want to type in a unique name (for example servername)
7) Then choose which one you like. I would suggest NOT choosing no-ip
Cool Under "Host Type", choose "DNS Host (A)"
9) IP ADDRESS should automatically display your current IP address. If this is incorrect, you can change it, but it really doesn't matter because the client will update this for us.
10) "Assign to Group"
11) "Allow Wildcards" is optional.
12) Click the "Create Host" button to continue.
13) You should now get a screen that says something about the hostname being added. It is USUALLY instant but can take up to around 5 minutes sometimes..
14) Download the client, from here: http://www.no-ip.com/client/ducsetup.exe
15) Install it, and and if asked select YES you want to install it as a service!
16). No-IP should now open..
17) It will either display a small setup window when you first install it, or you will have to click the "EDIT" button. In either case, you want to type in the address and password that you setup your no-ip account with.
18) Click OK.
19) There should be what ip thing you chose in the box. Tick it, and a smiley face should appear.
All it`s done !