300937 Zip Code Search

I have a classified listings website. It has 6 or so sections that users can put in keywords and search. I want all of those searches to be able to search by a distance from the zip code that they enter and be in ascending order. I use an access database. I also have another project. I bought to asp scripts, One is the classifieds above and there is another one. They both have users that use a different database. I want the databases combined so they both read off of one, so a user wouldnt have to set up a new user name for both sections of my site.