O rly?
If you prefix the url with http:// it should show up as link automatically
So [quote=http://www.google.com]moo.[/quote] works.
Links in the form of [url=...][/url] in the "Originally posted by" part of a quote have never worked afaik, not sure if this was some kind of limitation..
If you want a [url=][/url] tag in that part, this is how I've done it in the past:
[quote][i]Originally posted by [url=http://www.google.com]google.com[/url][/i]
moo.
[/quote]
or
[list][size=1]quote:[/size][hr][i]Originally posted by [url=http://www.google.com]google.com[/url][/i]
moo.
[hr][/list]