developing instant messaging app for mobile devices?

what technologies would be required to achieve this?

[distorto]

I know that some instant messaging services are available on mobile devices (yahoo and aim clearly...maybe there are more? what are they?)
What is required to achieve this? I work for a company that wants to develop a web application that provides instant messaging, but they are constantly mentioning mobile devices. I've heard conflicting reports about services that are enabled on many of the mobile browsers (javascript? java...on some)
Does anyone on here have any idea how hard it would be to develop something which could function as well as AIM or yahoo's messenger service on mobile devices?
I am not concerned with deployment in terms of developing relationships with carriers. I am looking at deployment as step 2. Right now I'm just trying to figure out if it's feasible to approach the problem.

[jtara]

I've heard conflicting reports about services that are enabled on many of the mobile browsers (javascript? java...on some)

Yup.

It's a total jumble. Your job now is to sort it out. ;)

Many phones - particular on GSM carriers - support downloading Java applets, which are sticky and resident on the phone.

Some carriers - in general CDMA, and notoriously Verizon, do not permit Java on their phones - at least those sold by the carrier.

The most popular browser does not support either Java or Javascript in browsed pages.

In some cases, a third-party browser written in Java can be installed by the user - but is not a very popular option except among tech geeks.

Verizon and some other CDMA carriers support BREW apps, which are written in just about any compiled computer language using a toolkit available from Qualcomm, and typically sold only through the carrier as a download. Verizon has a "free" IM app that really isn't free (you get charged for text messages) and is widely panned by users.

PDAs are a whole different world, with apps written in their native operating system.

Good luck!