Logrotate is a program that will periodically compress or delete your log files so that they don't wind up consuming your entire harddrive.
All the log files is works on are found in /var/log
However, when it takes forever and ever, it is most likely that you have used up most of your harddrive space and it is madly swapping stuff in and out of virtual memory in order to get the job done.
Also, you may have a misconfigured logrotate.
First of all you should do "man logrotate" to learn about logrotate (it is a good thing, trust me).
Then you should do a "df", which will show you how much free space you have on disk. If you disk usage is near 100% you have a problem.
Also, take a look at the logs in /var/log/mail, /var/log/news etc..., sometimes with a misconfigured logrotate it can end up re-compressing the same files over and over again leading to hundreds of files something like this:
....etc you get the picture...
Hunt around in your /var/log directory, if you see stuff like this for other logs as well, it's a good bet you have a misconfigured logrotate that is uselessly compressing the same file over and over again.
IIRC, the config file should be: /etc/logrotate.conf or something (there may be a config directory in /etc for logrotate, it should be easy to find...)
Anyways, if logrotate is misconfigured you will need to edit the config file to be more specific (i.e. instead of having it rotate /var/log/mail/mail.*, specify explicitly only the log files you want it to rotate) or to delete logs rather than compress them (if you really don't need a 4 month log trace or whatever...)
If you still need a hand, get back to me...