I am making a cake for a friends b-day party tomorrow night, I have made lot's of cakes before but they are never really smooth.
I always use buttercream and for some reason I can not get them to look smooth. The buttercream is the wilton recipe and another from a cake book I have. I think it's just my technique. Any suggestions???

You can dip a spatula in hot water to try and smooth the buttercream. Also if you get a paint guard/putty knife (12 inch) you can smooth the sides of your cake that way.

Using the VIVA paper towel method (detailed in various posts on this site) is also another good option.

I also have trouble smoothing my icing, it's a trial and error process and takes a lot of patience.

There is a post on this site started by Melvira describing a method for smoothing with a paint roller. The thread is I share because I care. The paint roller works wonders.

Melvira's roller method is great, I'll never use anything else again. I used it on my last two cakes and it is so much faster then the paper towel method and comes out smoother. Here's the link to her thread http://cakecentral.com/modules.php?name=Forums&file=viewtopic&p=433191#433191 Give it a try it's amazing.
Edited to correct typos