I'm using a "US.Robotics 9107A" 4 port ADSL router. With that i did register with the Dynamic DNS site also install the DynDNS software and obtain a domain name from them. But when i type that URL it jst give me the router control panel. not my web server. I also configured the vertual host fro a http service and a static route to my network where the server is up. I'm using Apache PHP MySQL setup as the server.

So what do i need to do? is there any configuration in my server or router to work that out?

It sounds like your router has occupied port 80 (the default port). Change your .ini's to run everything on port 8080. You may also have to change a setting with DynDNS. DO NOT, however, change the SQL port (it needs its own). Good luck!

For a start you can NOT use the domain name from inside the network, you need to type the machine's internal IP or name. To view it from inside by domain name you would need a dns server on your internal network, or to edit the machine's hosts file, either of these to point the domain name to the machine's private ip address. If you use an internal dns you must NOT allow it to appear on the internet. This is a hanging offence! On the router you must set port forwarding for port 80 pointing to your server machine's private address. Any other ports required need the same. Do not expect miracles from ddns, if your ISP's dhcp forces regular changes, expect 12 to 24 hour delays in propagation of the changes round the internet. Any more help, contact me.