While working through Level Four you may wish to download some new software. You can do that by clicking on the hyperlinks given below.
You may want to get a decompression program.
If you're using a Mac and you don't already have Stuffit Expander the easiest way to get it is to download Netscape
One of the plug-ins to try is Real Audio
You may also want to search for particualr software at the following sites. Shareware.com