A little help...

You can click the little gift icon to make it a gift url, then throw the url on the forums.

There's a little gift box to the right of where the key would usually show up, click that and it should bring up an option to e-mail a gift url or something of the sort (I haven't used it, so I don't know precisely how it works)

If it's the keys from older bundles, you have keys like you did when you purchased them. You know what to do with those. If it's one of the new ones, do not redeem the game, but click the icon showing a little gift, right of the game and steam field.

You are able to send what Humble Bundle call slices to other people, they can then add them to their Steam account through the Humble Bundle site.

If it is a spare from the bundle, it should work fine. Other's have been doing it.

I see what you mean. Just hit gift key and use the link then enter the email. Cool stuff and thanks again :D