Instant messaging is one of the simple pleasures of the Internet. You just type and send, and your online buddy has your message in an instant.

Many of the major instant-messaging services are piling on features such as audio and video chats, games, photo sharing, animated greetings, Internet radio channels and more. But ultimately, the instant-messaging service that's best for you is the one most of your friends and contacts use. Here's a comparison of the major services:

AIM

America Online's instant-messaging service remains dominant in the field. You don't have to be an AOL subscriber; the Windows and Macintosh software can be downloaded at www.aim.com.

The latest version, AIM Triton (only for Windows), ventures into true video chat, dispensing with fuzzy images and jerky motion. For me, the problem with Triton video was getting it to work. It took more than an hour to set up my first video chat. Each subsequent chat was easier but still not trouble-free.

Also annoying are the ads that AIM runs at the top of the buddy list or inside the chat boxes.

But the new text-to-cell phone feature was welcome. Even if a contact is not signed on to AIM, you can send a message to his or her mobile phone.

ICHAT

Apple Computer's service, included in the current Macintosh operating systems, debuted in 2003. It has never been bested.

Its clean interface allows instant messaging with AIM users and other iChat users. Apple has not added many frills to iChat, but what it does — text, voice and video chat — it does beautifully. And there are no ads.

MEEBO

This service (www.meebo.com) goes beyond the AIM/iChat combined buddy list by also including contacts who use MSN, Yahoo and other IM providers. You can do all your messaging from one Web-based list.

The main problem at the moment is that you must keep the full Meebo page open. It's more awkward to use than multiple messaging windows.

Also, if you do like video, audio and other extra features, you can't access them from Meebo.

MSN MESSENGER

The latest version of this Microsoft service adds frills to instant messaging, including little animations. The dancing pig, for example, was amusing the first couple of times I saw it.

Several games can be played with a messaging partner, but some of the fun is lost amid delays in updating the game board.

The video chat sported a good, fluid image, but setting it up was a nightmare.

The service can be downloaded at join.msn.com/messen ger/overview. The Mac version does not offer the advanced video, games and other features but has a user-friendly interface.

YAHOO MESSENGER

Yahoo has the smoothest setup and most trouble-free new features. Only minutes after downloading the most recent version, Yahoo Messenger With Voice, at messenger.yahoo.com, I was trying out the games with a chat partner, listening to Internet radio music channels, sending text-to-phone messages, having audio chats and sharing photos. The photo-sharing feature — drop and drag several pictures into the chat box for transmission — worked effortlessly.

Yahoo's new "super" video chat mode was a big disappointment, however. It looked good only when the video window was postage-stamp-size. At full screen, it was a jumble of pixels.

But the games worked great, to the point of being addictive.