Here is a list of four different all-in-one instant messeging web applications for Apple iPhone’s Safari mobile browser:

Meebo iPhone: This was one of the first services to introduce support for Apple iPhone. It offers support for AIM, Yahoo, Google Talk, and Windows Live MSN messenger services. To log into Meebo for iPhone, simply visit meebo.com from your Safari mobile browser and you will be redirected to the iPhone version automatically.

JiveTalk iPhone: JiveTalk is an alpha version of instant messenger that allows you to log in to all your existing IM accounts simultaneously: AIM/iChat, Windows Live MSN, Yahoo!, GoogleTalk, ICQ, and Jabber. Visit iphone.beejive.com from your Safari browser to use JiveTalk for iPhone

eBuddy iPhone: eBuddy is a new IM for iPhone and supports Windows Live MSN, Yahoo and AIM messenger service. This is an alpha version and might not be perfect. It supports emoticons and customization of message fonts and colors. You can visit www.ebuddy.com from iPhone and will be automatically redirected to the appropriate version of eBuddy for iPhone

Trillian iPhone: This IM client is currently in private Alpha testing and supports Windows Live MSN, Yahoo, AIM, GTalk and Jabber. To sign up, click here.

Some of these mobile IM services can even be used from the mobile xHTML browser of Nokia S60 mobile devices since they are based on Safari core.