xtail

watches the growth of files. 

It's like running a "tail -f" on a bunch of files at once. 

You can specify both filenames and directories on the command line.

If you specify a directory, it watches all the files in that directory.  It will notice when new files are created (and start watching them) or when old files are deleted (and stop watching them).

 Original software: http://www.unicom.com/sw/xtail/