glogg is a multi-platform GUI application to browse and search through long or complex log files.  It is designed with programmers and system administrators in mind.  glogg can be seen as a graphical, interactive combination of grep and less. 

httpsum is a highly configurable log file analyzer that lets you filter and summarize Web hits.  Its powerful filtering mechanism will let you generate custom analysis summaries after transformations and filters have been applied. 

zLogFabric is an all in one cross-platform logging solution that collects log lines/messages over a messaging system to a central server instance.  The modular design enables the server to store, forward, alert, and generate live statistics out of the logged data. 
It can collect log information from files, syslog, log4j, log4net, and Windows event logs.