64 bit is still x86 (if you have an x86 compatible cpu), and still uses the same architecture and assembly language. also, the 64 bit is also known as 80686, 686 or i686. the highest 32 bit system is i586 currently.

and as your username suggests, there is no such thing as an x64 architecture.

and no, technically, limewire is not a 32 bit program. the software is compiled as java byte code, which means the jre can read it universally. its like the english language. its a standard comunication language between all languages. (and its actually a requirement for politcal office in most countries.)

the byte code that the java language is also like an encrytped message, and is not runnable until its decrypted. and its not really runnable after decryption either. this is what the jre does, its decrypts the byte code and then it runs it as if it was running a script. so the only thing that needs to be natively programmed is the jre itself. the rest doesnt need porting because it will still decrypt and run the same script (limewire)...

make any sense? i know its a bit confusing, but it shouldnt be too hard to understand. its actually harder to put it into words than it is just to know how it works