While looking for some great Wireframe stencils recently, I stumbled upon Michael Angeles' templates available on his website. The stencil set is wonderful and really makes creating wireframes quick and "easy" in Omnigraffle Pro.
Talking of wireframes, I remember a time when I didn't think they were necessary for smaller projects. Although this might be true, it's definitely not the path that I recommend. During any design process you're bound to make many changes. It's much easier to make these changes while in the design phase than after you started coding. You'll end up with a more streamlined result if you don't rush through the design phase.
You need to think about the user experience before any design elements are in place. Think of the flow. Does it make sense? Think about the intent of each and every page before you type your first line of code.