There is no membership, only 6 months of free upgrades for 18.88 (pro version). Seems to me you have bought something at scam site:mad: Please say where you saw that, you've been had! Now be more conscious of your purchases next time...
Ciao
Edit: Prices as of 2008 are: Lime Wire » Download LimeWire _ Pro for 6 months support $21.95;
_ Extended Pro support lasting 12 months for $34.95