If you installed WebLogic in the default location, then the location of this and many other useful JARs to have on your classpath is /root/bea/wlserver_10.0/server/lib
If your "Deploy to WebLogic" Ant tasks (or like that) are failing, you can put this in Ant's classpath. On Eclipse you do that this way: Window > Preferences > Ant > Runtime > Classpath > Global Entries then Add External JARs.
If you run a jar -tf weblogic.jar | less, you can browse through them, but this is a lot of items, so you can also just output the contents to a file:
> jar -tf weblogic.jar > /home/ehewitt/WEBLOGICJAR.txt
But that is a huge file. Limit the output to listing only the Ant task definitions in that weblgoic.jar:
> jar -tf weblogic.jar | grep "weblogic/ant/taskdefs*" > /home/ehewitt/WeblogicJarAntTasks.txt
That produces 93 items for WebLogic 10.0, including our WLDeploy.class.