Just above the textarea that you use to enter the message text there is usually a button bar with buttons to add text formatting like Bold and Italic.
That toolbar may also have a button to turn a text link into a clickable hyperlink (look for a chain like button).
You can select the text and click that button to turn the link into a clickable hyperlink.
If you can't find the button then hover them all to check the tooltip of each.

• Make Link - https://addons.mozilla.org/firefox/addon/142

Great - thanks a lot! Shame it's not automatic though, as it is with IE etc.....

You're welcome.

Hi, same problem. The message contains a proper link (little hand appears when hovering above it). When I click the link in the message, FF opens up with a new tab but then just sits there. This used to work for FF 3.6, but after upgrading to FF4 I have to manually copy and paste the link into to the awesome bar. Any ideas??

I have encountered the same problem with newest Firefox 6. Used to be able to just right click and get a hyperlink for url to paste into e mails. Firefox used to work great, now with the constant upgrades, all the add ons and even basic features are becoming more problematic. wish they would just concentrate on supporting one version to the best of their abilities and quit requiring so many updates that don't work as well. Many friends are migrating to Chrome....I am trying to stay with firefox because it was so good for so many years, but now it seems like constant problems. Hope they get it worked out soon or I might have to follow the flock in migration.