GUI for watching logs (tail and grep)
Solution 1:
I've discovered glogg, which describes itself as:
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.
It will also tail files if you enable the Follow File option.
Just search Ubuntu's Software Center!
Installation through command line:
sudo apt-get install glogg
Solution 2:
Multitail is what you searching for:
it has tons of features. look here for some screenshots.
Also have a look at this question over there at serverfault.com
Solution 3:
Some options are: Swatch and KSystemLog
There's a log viewer built into Ubuntu, which can also open any log file, called System Log.