If you're one of the few people still running Mac OS 9, also known as Classic, then you should really update to OS X, as less and less applications still run on Classic these days. Fortunately for you, a supported version of LimeWire is still available.
You'll find this version of LimeWire very easy to use and full of help. The interface itself makes it easy to connect to servers and monitor your different downloads. Of course, it will look very outdated compared to the more recent version of LimeWire and will probably not perform as well, however you'll probably already be accustomed to this in Mac OS 9.
If you open up the preferences you'll see you can adjust a number of parameters, like setting bandwidth speed and limits on downloads and uploads, selecting your port or deciding where to save downloads or what files to share.
LimeWire also includes basic playback functions to preview your download and make sure it's what you were searching.
If you're still running Mac OS 9 and are into peer-to-peer (p2p) downloading, then you should install the friendly and easy-to-use LimeWire.