You're right, Clearwire are known to throttle & block p2p.
Clearwire Broadband - Irish ISP Test - Broadband Forum - How Fast Is Your Connection?
Clearwire Broadband - boards.ie

There was one person who posted here, who could get a connection & even got some reasonable download speeds
http://www.gnutellaforums.com/downlo...p-address.html

Make sure that the XP firewall's configured to allow LW.
User Cant Connect - LimeWire

Some people have had connection issues with Java 1.6.0_01. Try this version instead. Use the JRE offline installer & remove your current Java version before you install this one.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11

Change ports in LW. Tools > options > advanced > firewall config, change LW's listening port to 64049 > apply > ok. You can also try other ports in the range of 49152 - 65535

Set up port forwarding for your router. The instructions are here.
Port Forwarding for the Linksys WRT54G
Don't forget the step of setting up a static IP address first! LW's listening port, port in the 'manual port forward' box & port forwarded within the router have to all be the same number!!