How do i make these videos?

Ok well its a split screen with 2 videos and audio put behind it. like the audio is clear is not in the video, he added it after.

YouTube - The Beatles - Birthday (Lead Guitars)

and how do i make a slideshow with music like this?

YouTube - The Beatles - "Helter Skelter" (Anthology Version)

thanks a lot!!

Well the first one you would need something like final cut, as it looks to me like it's just one video track over another, with the opacity turned down on the top one.

The second you could make in iMovie i suppose, just add the pictures as you would video clips.

The first one is just two video tracks laid on top of each other with some sort of a gradient effect between the two. I'm not sure if it can be done in iMovie, but it can be done in FCE or FCS.

The second one is an overly slow slide show - the pics are on for WAY tooo long IMHO. I don't like looking at a single image sitting there for 20-40 seconds. Rule of thumb I use is 4-6 seconds (usually either 4 or 5 seconds); even 10 seconds feels like an eternity. Now if there is text on the screen then being on longer for the viewer to read what's there is a different story. The second one can easily be done in iMovie. The zoom effect on the first image was just a Ken Burns style effect that is offered in iMovie. All you need to do is import your photos, lay them out, put any transitions between photos you want, etc. then take your music and lay it out on the photos. Granted you may need to add/trim photos if the song is shorter/longer then what you expected.

Edit: Sheesh, I just can't type fast enough today, iZach beat me out on both of my posts today.

how do i get final cut? or where?

You can buy Final Cut Express (or Studio) from Apple or an Apple reseller (or on EBay). Brand new, FCE runs ~$199 (maybe less, but I think that's the current price) in the store.