I have been asked to make a princess castle cake . Its needed in 5 days time. So i dont have long at all. I have never made one before and dont have the Wilton set. I was wondering what is the quickest and easiest way to make the towers and turrets. Any advice would be great so thanks in advance

If you search the glallery on CC for "Princess", "castle", etc, you will see many that use ice cream cones for the towers. Cake cones for the towers, sugar cones for the peaks. I am going to be doing this in two weeks also!

Yes, I was going to suggest what she ^^^ said. I made one using cake cones, "glued" end to end for the towers with sugar cones for the turrets. One little suggestion: set the cones out for a couple of days so they will get stale. They will be easier to work with. Also, if you cover them with melted chocolate or candy melts, they won't swell and crack if they have already absorbed some moisture from the air.
Here's the one I did in this manner:

http://www.flickr.com/photos/hjscakes/3208641830/in/photostream

Also, I just remembered this little cake I made for my great niece...I used paper towel rolls as the form for fondant towers. I covered the rolls in waxed paper, formed the fondant around them, and slid them off after about 24 hours so the inside would dry as well.

http://www.flickr.com/photos/hjscakes/5198211757/in/photostream

Check out these links:

http://www.make-fabulous-cakes.com/castle-cake.html

http://www.thebamboosprouts.com/?p=291

Great links- thanks!