How to distribute a file to multiple clients efficiently?

I am building an application which, hopefully, will be installed on many clients (desktop and mobile). Client A may generate a file and publish that he has it. Clients B-Z may decide they want this file.

Some assumptions:

• files are ~2MB.
• When one client generates a file chances are most other clients will want that fil开发者_如何学Ce. I guess this is not the case with most P2P apps.
• I cannot afford an expensive server farm.

I am thinking to use the bittorrent protocol.

Is it a good approach assuming I use a public tracker or DHT?

Not sure which programming language you are using.

If you are using a .net language you could use MS Sync Framework (which is free) See: http://msdn.microsoft.com/nb-no/sync/bb980926.aspx