Here is a short tutorial on how camera works:

basically, you must first CREATE the camera like this:

<camera mode="create" name="bob" pos="0,0,-150"></camera>

this will create a camera called bob, and will give it a position.  the cameras 
rotation will be set to 0,0,0 by default.  the cameras 'viewport' will be set 
to fullscreen, the viewport is the area of the screen the camera will show in, 
so 0,0,0.5,0.5 will mean it will only draw to a quater of the screen and will 
appear in the top left corner.  So you can also create a camera like: 

<camera mode="create" name="bob" pos="0,0,-150" rot="0,0,0" 
viewport="0,0,1,1"></camera>

once the camera is made you want to tell an effect to use it.  If you have a 
skybox effect:

<add type="skybox" name="sky"></add>
<skybox file_top="top.jpg" file_left="left.jpg" file_right="right.jpg" 
file_bottom="bot.jpg" file_front="front.jpg" file_back="back.jpg" 
camera="bob"></skybox>

and you can change the camera at any time: <skybox camera="bob2"></skybox>

but this will just give you a static camera..useful for somethings, but if you 
want the camera to move you need to add keyframes.  keyframes are snapshots of 
camera settings at certain times, the camera will blend between these 
keyframes.  to specify keyframes:

<camera name="bob" mode="keyframe">
<key t="0.0" pos="0,0,2"></key>
<key t="200.0" pos="0,0,-2"></key>
<key t="400.0" pos="0,0,2"></key>
<key t="600.0" pos="0,0,-2"></key>
</camera>

t is TIME
pos is position (XYZ)
rot is rotation (XYZ)

this will make the camera go forward and then back, then forward then back.  
it'll happen over 600 'frames'.  The further apart the keyframes, the longer 
it'll take to blend.  at the end, it won't loop though, i need to add this 
feature.  You can also animate the cameras rotation:

<camera name="bob" mode="keyframe">
<key t="0.0" pos="0,0,2" rot="0,0,0"></key>
<key t="200.0" pos="0,0,-2" rot="0,0,180"></key>
<key t="400.0" pos="0,0,2" rot="0,0,0></key>
<key t="600.0" pos="0,0,-2" rot="0,0,90"></key>
</camera>

this animation the camera will rotate around Z (like turning your head).
try it out, i have some EXAMPLES of this camera script being used:
http://www.rawhed.com/tmp/crazy_v3.rar

