I'm no expert, but i've been hacking phpShop for over a year now (about 10 sites that don't even resemble the original anymore).
concerning the Contact/About Us additions.
i've found that the best route is to keep it simple, but stick to what's already there. this may be overkill, but it works.
you've already got a database to house the content - use it. copy the shop/ directory completely to a new folder called contactus or whatever. create a new category in the products list called contactus - leave it unpublished. add a product under it called contactus, and put in the content you wish to have appear - leave it published. in the contactus/html folder you copied, edit the index and browse IHTML files to strip out the functions you don't need (like the Add To Cart buttons and pricing displays and such). change the format of the content as desired as well. here's the trick - don't have it SELECT data based on values passed in, but hardcode it to pull the products listed under the unpublished "contactus" category instead, either by category_name or category_id. all you really have to change is the SELECT statement - you can keep the display and navigation mechanisms the same. also, update the menu file to reflect what you'd like to be there or not. finally, as Administrator, you have create a new module based on exactly that of the existing "shop" module, changing what need to be changed to reference the "contactus" folder.
to integrate into the rest of the site, edit the template/s_header.ithml file and add the link to the nav bar across the top, formatted just like the Home link, but using contactus instead.
as a note, you can also copy the s_header and s_footer template files to new templates (contact_header and contact_footer for example) and reformat those temlates as well, further changing the look of the contactus section. you'll need to specify the new templates when you create the new module as well.
works like a charm, and you end up with a more powerful CMS system out of the deal. playing with the template and contactus ihtml files, you can change the layout and display features for just that section without affecting the rest of the site.
i typed these instructions up quickly, so there may be some vague references, but poke around, and respond if you need something clarified.
