This is in continuation with my previous post about MSN China releasing an official Symbian 9.1 based Windows Live Messenger for Nokia S60 2nd and 3rd edition devices.
MSN China also lists a Java J2ME based version of Windows Live Messenger for other devices such as Motorola and Sony Ericsson. Unfortunately, there is no SISX based client for Sony Ericsson UIQ 2 and 3 devices like for Nokia, but the Java version isn’t too bad either.

1) So head over to http://mclient.msn.com.cn/
2)
For Motorola devices, choose the 2nd option in the first drop downdown box in Step 1
For Sony Ericsson devices, select the last option in the first dropdown box in Step 1
Select your phone model in the second dropdown box in Step 1 itelf
3) Then click on the PC box to download the client.
It wil be a JAR file. So first transfer it to your mobile device thru the phone software provided to you and install it directly from the mobile.