How flash handles sound

Hi to you all
I am a web newbe, I have just got domain name and hosting hooked up.
I am about to design my first web site
The site is a music web site were I will be selling and giving away royalty-free music
e.g. Loops for web developers as well as sample CD’s for music production and tracks.

To the point at hand

How do I?

  1. Make a track or loop download-able. And have the ability preview the track as a low quality file before they down load track they want.

  2. I have herd of something called paypal for the shop side of things. Is paypal a good way to go for the novice as a shop front?

I will be using Flash MX and Photoshop 7

Thanks hope to here from someone soon.