If you looking for portable client for your Windows Live Messenger you can use Portable Windows Live Messenger 9 (2009). I suggest you to use this version because it seems that the lower version WLM 8.5 Portable is not work anymore.
Features in Portable Windows Live Messenger 9
The features in Portable WLM 9 almost the same as in official client of Windows Live Messenger 2009: emoticons, avatar, contact list, voice chat and many more. Of course, because it is a portable application, you don’t need to install the software. Just plugin your from you portable device than you can start to using it. Fast and easy
Free Download Portable Windows Live Messenger 9
You can download at the link below:
Portable Windows Live Messenger 9 at www.ncnblue.com (WLM 2009 (Build 14.0.8089.0726 / 53.7 MB)
For complete list you can find Portable WLM aka MSN Messenger at http://www.ncnblue.com/wlmportable/
Other Download Link: Download WLM Lite 2009 Portable