Here is a small tool I wrote that helps to parse those SharePoint 12hive ULS logs.

The left hand side shows your logs from the 12 hive, double click on a filename to load it.
The right hand side shows the log file in a grid view and allows for sorting on the column names by clicking on the header.
The bottom includes some basic filtering. At the moment, it only allows for one filter at a time, I am working on allowing multiple filters.