Use the "Instant UBB Code" for "URL." When the window pops up and asks for the URL address you want to link to, type it in or paste it in and click OK. Another pop-up then asks you for text and you type in the text for the link. I like to use names like "sausage link," "chain link" or "cuff link," but you can type anything you want. It won't affect the way the link works - just the way it looks.
On some forums, the link will appear as blue, on some it will be underlined, on some it will be both. This is one of the unfathomable mysteries of The Grumble. If you insist on having it appear blue and underlined, you can use the appropriate HTML codes, but I can't go into that right now.
<U><font color=blue>This is not really a link</U></font color>