1master1 - Looking at the input fields, you may wish to reconsider using so many text-boxes; by using drop downs/checkboxes you can use filters more effectively. It will also prevent TOO many spelling mistakes
also - just an idea - rather than having a box for the company details, you could offer this as a package - so companies add their details to the existing links directory (for example) then, if they are a company in the links directory you don't have a text area, but a link to the links directory listing.
Its also an idea to think about if you want these job listings to show on say the portal - as a list of new jobs - or even to have a special box on portal or index with a featured job (these two plugins already exist here on mybbhacks).
Another nice touch would be to use the similar thread prefixes plugin to show jobs with a similar prefix - so its an idea to choose one of those fields in the list to be a thread prefix so you can use that feature.