if your authoring app supports that function you can. DVDA2 does not support it and Im unsure fi DVDA3 will or not. The only two apps I have seen supporting this was Apple's DVD Studio Pro 3 and Sonic Scenarist. Its possible Adobe Encore does but I have never used that feature.
Go to www.sonic.com and check out their eDVD product.
The ability to link to a web site like this typically requires that the player software support the ability to do this based on cues from the DVD structure - there's nothing that you can actually embed in the DVD only information to do this.