Normal scheme:

h-t-t-p-colon-slash-slash-w-w-w-dot-a-v-dot-com

BBC scheme:

(h-t-t-p-colon-forward slash-forward slash)-w-w-w-dot.-a-v-dot.-com
In the old days, they used to say oblique instead of forward slash. I swear I'm not making this up.

Patrick Moore scheme:

h-t-t-p-colon-slash-slash-w-w-w-stop-av-stop-com
Dear old Moore seems to have gotten confused with telegrams.

NTK scheme:

yadda-yadda-yadda-dot-a-v-dot-com
Nice and flippant, as we expect from these guys.

When in Norway:

Treble-you-dot-a-v-dot-com
According to SharQ, who would know.

See also "Oo" for Oolong's slightly odd pronounciation, based on Welsh. And, of course URL should be pronounced "ural", not u-r-l.