Illustrator is much better than Photoshop when it comes to line art, so I'd get it if you can, but you can certainly get by without it. There's a quick tutorial on Polykarbon: [url=http://www.polykar ...
I agree with Basement Bound that some pages are weak, but once you get the logos up for those it should help. Just be careful to keep some unison in the pages. When each ...
I think this drawing has a lot of potential if you clean up the lines a bit- I'd especially recommend going over the black lines with the paintbrush set to 100% opacity.