I want to make a Job Portal, What are the things required and what capabilites my hosting company should have ??
You're going to need a server-side programming language and a relational database management system. PHP and MySQL are good examples of the two, are both free, and are also commonly found on most Web hosting providers. Depending on how much traffic you get, you may be best off leasing a dedicated server, but if you do so, you're going to have to make sure you can maintain it, hire someone who can, or pay your hosting provider an arm, a leg, and your first born (figuratively speaking of course) to maintain the server for you.
Check out the list @ http://www.hotscripts.com/PHP/Scripts_and_Programs/Classified_Ads/Employment/index.html or a Google search should give your more than enough information to follow up on.