There are several threads on this very topic in the Before You Buy section; just take a look and you'll find several with the information you want.
In a nutshell, we do not have product pages available on our site just yet - they are under development.
We do not allow transfers of licenses as these are two distinctly different products.
Yes, you can purchase vBGallery, there is a sticky at the top of the Before You Buy forum explaining how.
Same level of support, we have vBGallery staff members patroling the vBG forums.
Please do not PM me for support or sales questions. Thank you for your understanding.