Yahoo Messenger 9 has the following features (all available in Win XP) and part of them available in Vista, MAc or Linux:
Send text messages in real-time to your friends on Yahoo! or Windows Live™ Messenger.
Join a chat room to meet new friends while you discuss your favorite topics.
Share photos from your desktop or Flickr, then discuss them over IM while you and a friend view them together.
Make a voice call to another Yahoo! Messenger user for free (microphone and speakers/headset required).
Phone Out (PC-to-Phone Calls):
Call friends on their regular or mobile phones from Messenger for as low as 1˘ a minute (Phone Out account required).
Phone In (Get a Phone Number for Messenger):
Get a new phone number that allows you to receive calls in Yahoo! Messenger (Phone In account required).
SMS (Text Messaging):
Send text messages from Messenger to your friends mobile phones for free.
Plug in your webcam to share live video with your friends on Yahoo! Messenger.
Instant message with many friends at once in a conference room (includes voice capabilities, where