The old version of iSerial Reader (version 1.2.4) has been expired. The good news is iSerial Reader 2.0 has been released along with the 05/2007 Serial Box. You can download it from serialz's web site.
I'm not going to provide the link to the download location. I think you should be smart enough to get the URL from this article. ;)
BTW, for those who doesn't know what iSerial Reader and Serial Box is, according to Serialz,
"iSerialReader is the tool for reading the SerialBox and now works in OS X, OS 9 and Windows. It is a small application that contains serial numbers for most popular Mac applications. It is updated monthly and can be downloaded here."
Again, who said Mac doesn't have software? ;)