It would look neat if you made the top tier red and then piped a spiderweb on the top and draped it down the sides of the top tier. You could make the bottom layer a royal blue with his name in red. You could buy an action figure to place on top so that he could play with it afterwards. I just saw a commercial for WalMart and they have all the new Spiderman 3 figures now. I'm sure you could find one that would work. Good Luck with it. I know he will love whatever you come up with. Post some pics when you're done. 
I am a beginner too and would go the easy route - for me, I would do a sheet cake w/ streets. Then form sky scrappers out of rice crispies. It would be easy, colors well and molds great. Then sit those on top of a sheet cake Then you could buy a figurine and attach him to the building. I know they have several characters that you could add around the town as well.
Good Luck! Please post a picture!
Quote by @%username% on %date%
%body%