HTML Frames Information Needed

Hi : Im just about to start desinging a site for a client and it will be using ‘Frames’. I havnt done much work with frames, so I was just wondering if anybody can answer these questions that I have to ask below:

  1. Im going to have 2 frames, a top frame and bottom frame so basicly the page split into 2 halfs. Although iv drawn my layout in photoshop already as one whole piece, if crop the top frame part and the bottom frame, and then stick each part into a frame, will both parts line up correctly so you cant see the frames? So the design will just flow through…

  2. Iv seen some sites use things such as " i-Frames " is anybody able to quickly sum up, what iframes are?

If anyone is able to help, would be appreciated, thanks in advance Ben.