COCOAJUNKIE  Pros:

- Easiest way to share music from iTunes over the web

Cons:

- Webpage is broken on IE 6 on Windows, although it looks fine in Firefox

- No way to browse by artist or genre. You would have to create a separate playlist for each artist/genre.

- Doesn't stream music. Songs are downloaded over the web. I would like to ocassionaly let a friend listen to a song purchased from the iTunes music store without giving away my music store credentials.  
(Version 1.0)

COCOAJUNKIE  Great little app!

Integrates well with the web browser (I use Camino) using either the bookmarklet or a keyboard shortcut.

I love how it auto-completes tags and displays a Growl alert when items are posted.  
(Version 1.1)