Cutting a hole on the top of a cylinder

well, i am a noob at blender, and i cannot figure out how to cut a circular hole in the top of a cylinder. i need to cut 6 holes, so does anyone know how to do this? any help would be nice thanks!

With booleans it should be quick.

It works the same in both 2.49b and 2.55

First get your cylinder, and 6 other cylinders where you need the holes to be done.
The 6 cylinders must be joined as an object (Object Mode -> Object -> Join or CTRL+J)
The big cylinders must be a separate object, it must not be joined to the 6 littles ones.
http://img525.imageshack.us/img525/5923/clipboard01oj.jpg

Move the 6 cylinders so they intersect your big cylinder top, roughly like this :
http://img340.imageshack.us/img340/7381/clipboard02hm.jpg

Now select the big cylinder only
http://img155.imageshack.us/img155/8750/clipboard06b.jpg

Add a Boolean modifier, set it to Difference and at Object select in the drop down menu the name of the object that is made of the 6 cylinders.
http://img651.imageshack.us/img651/5623/clipboard07k.jpg

Press Apply.
Select the 6 cylinders object and delete it

http://img560.imageshack.us/img560/1913/clipboard08.jpg
http://img155.imageshack.us/img155/2888/clipboard09s.jpg

For 2.49b it works the same, except you have to type manually in the boolean modifier the name of the 6 cylinder object.

In 2.49b you have an alternative to using modifiers, that is not implemented in 2.5x.
After you have placed the 6 cylinders object where you need them to build the hold on top of the big cylinder, you select the big cylinder first, then press SHIFT and select the 6 cylinder object so both objects are selected and the cylinder has been first.
http://img708.imageshack.us/img708/2466/clipboard10r.jpg

Then press W (or Object -> Boolean Operation) and select Difference.
http://img405.imageshack.us/img405/9785/clipboard11n.jpg

Then you press Delete (as Boolean like this create the object as a copy) to delete the original 2 objects that are always present.
http://img88.imageshack.us/img88/3416/clipboard12n.jpg
http://img843.imageshack.us/img843/7195/clipboard13p.jpg

Note that Boolean can be very unreliable if one of the object has inverted faces, so make sure their normal are correct.

Thank You!