Abnormally Large Files

I did a disk inventory on my hard drive, and i found two files that seem to be abnormally large. One is a a document that is 2 GB and the other is a .log file that is over 9 GB in size!! Here is the info on the file:

File name: sleepimage
Kind: Document
Size: 2 GB
Date Modified: Today (When it woke up from sleep this morning)
Date Created: 6/10/07 (The day I got my mac)
Owner: root
Group: wheel
Permission: -rw------ T (600)
File Path: Macintosh HD/private/var/vm/sleepimage
Format: HFS+
Mount Point: /
Device: dev/disk0s2

File name: windowserver_last.log
Kind: LogFile
Size: 9.2 GB
Date Modified: 11/19/07 7:39 AM
Date Created: 11/18/07 10:50 PM
Owner: (blank)
Group: (blank)
Permission: -rw-r----- (640)
File Path: Macintosh HD/private/var/log/windowserver_last.log
Application: Console
Format: HFS+
Mount Point:/
Device: dev/disk0s2

Is there a way that I can get rid of this? Do other people have log files this size?