Mercury supports webcams and works like ms messenger:
Be sure to download the beta, the stable one doesn't support conference....
What is Mercury ?
Mercury is a Java-based MSN client (and upcoming Jabber client)
With Mercury you can do the same things as with your normal messenger:
Talk to friends
Change your nickname and status
Add a display picture (also know as avatar)
Send files through the msn server (for people with a firewall etc..) or direct
Play games (Tic Tac Toe and Connect4 only at the moment)
Watch the webcam of your friends (Mercury auto-saves these sessions on the disk and can convert them to Quicktime movies, click here for more info)
Allow other people to watch your webcam
Video conference is implemented (both sending and receiving) but still a beta feature.
Send and receive winks (sending custom winks doesn't work yet due to new security restrictions in MSN7)
Showing your current song, directly using winamp on Windows, ITunes on Mac OS X and a shell command on every OS
Send and receive nudges
Receive voice clips (sending is not yet supported, the audio codec is probably Windows only so I don't feel doing research on it at the moment)
But Mercury has some extra functions that your normal messenger doesn't have, for example:
Support for multiple operating systems, you can run the same Mercury version on Mac OS X, FreeBSD, Linux and Windows. So the Mac OS X version isn't 2 years behind ;-)
Be online with several MSN addresses at the same time.
Login with your status on 'Invisible' or any other status you want.
Have a different MSN name in every conversation (Personal name)
Use and create your own plugins
See when someone starts a conversation with you before he says something (this has been removed from MSN7, Mercury will now show when someone starts typing, this is the closest I could get to the old function)
See when someone closes the chat conversation window.
See who added you into a conversation with multiple people
See when someone deletes you from their contactlist.
See what MSN client version someone is using (or emulating, Mercury currently emulates 7.0)
See if someone in your list is using Mercury
See if someone in your list has a webcam (if he/she allows you to see it)
See your fake, faked and ghost friends
All avatars downloaded are stored on your computer in PNG format (96x96)
All webcam streams are stored on your computer, you can convert them to a Quicktime movie if you want or watch them internally using the webcam stream player
All personal emoticons downloaded are stored on your computer
Avatar scroller, automaticly change your avatar every 5 minutes
Background image scroller, automaticly change backgrounds every x minutes
Send larger avatars then normal
Override someones avatar
Enter notes while in a conversation you might need later (date of birth, last name, phone numbers)
Away message, if you are online, busy or whatever you can always have an away message.
Disable the away message in a conversation so you don't see that annoying message when you just want to talk while appearing away to others
Auto log chat conversations, always log your chats so you can read back everything that is said between you and your contacts.
Auto login multiple accounts on startup.
Auto away, change your status to away (or anything else) after x seconds of idle time (Windows only)
Auto update when a new version is available (Mercury asks if you wish to update when new version is available)
XML and text based chat logs
Customise all menu bars.
Customise your contact list:
Hide offline contacts
Show contacts by email, MSN name, alias or a combination of the above, supports multiple lines (List view)
Change the status icons
See the difference between contacts using Mercury, contacts having a webcam, fake friends and more
Show display pictures in the list (lastest beta release allows you to specify the size of the image in the CL)
Show emoticons in the list
Sort contacts by group, status or both
Show contacts in the program by email, MSN name, alias or a combination of the above (General view)
Add new status icons
Mercury has 10 custom skins and 3 java skins
Send screen shots to your contacts
Add more then 12 users in one conversation (MSN messenger limit)
Specific triggers for each person (trigger = action after chat event)
Supported actions for a trigger include sound, a popup window, a windows balloon (balloon=Windows only), shaking a window
Support for Growl
Special codes in your name.
Nick scroller, change your name every 30 seconds into something complety different (allows the usage of the special codes)
You can use 'forbidden' words in your name.
You don't have to worry about Messenger worms and virusses, they wont work on Mercury(Windows only :P)
XML based setting files.
Downsides of Mercury:
It requires a pretty fast computer if you want to take full advantage of all it's functions. Since I am using Swing to display the user interface almost no native widgets are used. This can slow things down on older computers.
Not sure if you can call this a downside, but Mercury was not made to be exactly like MSN Messenger. It might take you a few seconds longer to find an option you need. I'm not trying to make a MSN Messenger clone so the user interface is different...