Can you please edit your profile and include a location? Even if it's just your country of origin. We have a pretty broad user base and it helps us give you advice that will actually pertain to the country you live in. Thanks!
Good luck in your search, they do come up for sale from time to time. They are not cheap though, you may have guesed that from looking through the various postings on this site.
The best advice I can give you is to put some money away for when they come up so you have the cash ready. In the mean time, as you are new to the hobby cut your teeth on some community fish to gain a bit of experiance first. Try and get your head around water quality (the nitrogen cycle, pH hardness, phosphates, metals etc), temparatures feeding stocks etc.... When you have cracked this have a go!
If you do have any queries put a post up here, we are a friendly bunch and someone will answer your question.
Alistair
PS like mindy said please do put your location in as it makes it easier for us.
I agree with Alistair..you want to make sure you have the basics covered before progressing onto zebra's and spending large sums of cash.
I'd also recommend getting some BN's as they easier to breed but will still give you invaluable info and experience when you get onto the zebra's.