It's not a scam. Everything is described on their website. You get Pro with 6 months of free updates. Around the end of 6 months you can repurchase at a discount. Now what is scamming about that? Didn't you read about what you were buying? Sounds like you're just cheesed off because you forgot your 6 months of free updates has finished. That doesn't give you the right to call it a scam when there's nothing on the LW site that is trying to trick anybody. It's all there described ... LW pro with 6 months of free updates & support.
http://www.limewire.com/english/content/download.shtml duh!
There's no lifetime of free updates for Pro. Where does it say that on their website? Besides you can keep using the version you have.