is there a script that would place a button on a page to email the current page to a friend ? if not, perhaps it would be good!

Personally I just send people links to the page. I've seen that button on pages: E-Mail to a friend, and sometimes they ask for the eMail address, sometimes it's just a mailto link. I think it's silly, I just copy the link and paste it in the eMail, and I actually like to type a message to the person I'm sending to (otherwise I consider it spamming).
You can use the Send link... under File, but sometimes the URL of the page you're looking at is not what you want to send or it may not work for someone else (like if you're logged into the site).

Of course webmail (gmail) is different, there may be a way to do that, I don't know I don't have an account there. Still all it could do is copy the Location, open a new tab for your webmail and paste the link into the new message, if that's even possible. Is it that much of a hassle?

I found a script that converts mailto: links to work with Gmail, so apparently it is possible...
Curiosity is bliss: Handle mailto: links with Gmail:
http://blog.monstuff.com/archives/000238.html

and another one here...
GMailTo
The actual script - http://youngpup.net/userscripts/gmailto.user.js

So sending the Location of the current page wouldn't be too difficult at all, but I would have no way of testing it. For example gmail may require a recipient address for it to work, I wouldn't know.

yeah, the mailto gmail script was what made me think of this actually... yeah it is not a lot of work, but it would save a little time if you could just click a button or hit a shortcut key to bring up a new tab with a gmail message with the link posted in the message body. all you would need to do is type in recipient...

An extension would be better, like Email This! Bookmarklet Extension...
https://addons.mozilla.org/en-US/firefox/addon/...

Email This! will send your recipient the link, title, & highlighted text of the page you are viewing using GMail, Google Apps GMail, Yahoo, Hotmail and Stand-Alone Mail Clients like Outlook Express, Thunderbird, & More!

I haven't tried this but I like the idea that it sends selected text and the title of the page, since I often do that and it takes a few copy-pastings.

https://addons.mozilla.org/en-US/firefox/addon/...

edit:
looks like you beat me to it.. i installed it and it seems to work pretty good!

Check out the script for that gmail-mailto. It would be really easy to write in greasemonkey too!