The urls for video are as follows:
ActiveX:
http://[DEVICE IP ADDRESS]/aview.htm
Java:
http://[DEVICE IP ADDRESS]/aview.htm
If you are using Firefox, Safari*, or Opera, you can even put the username and password in the URL by adding it at the beginning of the address, just like you would an FTP site:
Example (for Java, with "192.168.1.100" as an example IP address of the device):
http://username:password@192.168.1.100/jview.htm
*If you're using iOS, please see the note below about Java on iPhone/iPad
But you can only use the java version for these browsers. This capability has been disabled in Internet Explorer and Chrome for security reasons, however, there is a workaround for IE. Here's the link for the workaround -> http://support.microsoft.com/kb/834489
For the iPhone/iPad, you will need Cloud Browse, or one of the Virtual Browser packages. They are $4.99. They will work, but the former is kinda crappy and only gives you the ability to browse for a period of time, and the latter option is a little buggy.
You have two other options, but neither is great. The first is to pull up the address on a computer, and Remotely connect to it using either an RDP or VNC app on your iPad/iPhone. With the video quality and framerate, you'll be surprised how faithful the representation is. The second option is to use CamViewer app, but the audio almost never works (once or twice it did, but I have not been able to find a rhyme or reason to how the heck it worked those times... DLink doesn't appear to have a compatible API).
Hope this helps.
To get the site to work on your iPhone/iPad, you will have to use Frash