Click the link below to download AlanC's "linkcreator" to easily make hyperlinks in the Sony Vegas forum.
Basically what it does it make the following text from a link and words you give it to describe:
[link=http://coolwebsite.com/folder][b]words to describe it[/b][/link]
So if you can remember the format above, you don't need this program.
Update: LinkCreator which now includes linking to images on websites such as Photobucket. Paste the URL of the image into LinkCreator and select 'Link to Image'
I've hosted AlanC's helpful app in the past for years at my other domain, it's still there too:
Why doesn't Sony make an easy way in their forum to create hyperlinks?
I have no idea...