Multi ICQ is the name of this software that would allow you to create multiple login which make you able to use multiple ID / more than 1 (2 or 3 or more ICQ IDs) at the same time at the same computer: ICQ Polygamy ID. You can use it in ICQ 6, ICQ Lite, or in ICQ Pro.
Download ICQ Multiple IDs
ICQ Ads Remover Advertisement Blocker
You can use this ICQ tools to remove ICQ Advertisement Banner by using Ads Remover.
Download ICQ Ads Remover

There are few alternative to use Windows Live Messenger on Nexus One (WLM in Android). Two Alternative below are the best ways that I recommended to your.

Use Meebo for Android
Use eBuddy for Android

Meebo and eBuddy are Multi IM Client that can connect to several Messenger Service at one such as Windows Live Messenger, FaceBook Chat, Yahoo Messenger, AIM, ICQ, and much more. That why you can use it to connect to Windows Live Messenger from your Nexus One (Android 2.1 OS)
How to install Windows Live Messenger Client in Nexus …

If you like to uninstall Windows Live Messenger from your computer without getting a “headache” you can use a small software called as Windows Live Messenger Uninstaller.
If you got a trouble or problem when you run WLM (on the installation process for example) your can remove any broken Windows Live Messenger installation file and the start to install the newest WLM Installer. We knew that the installation are not listed in the Configuration Panel that make WLM “very” difficult to remove completely. That is why I called that to uninstall …