I never saw any ad program, which shows ads in arabic langauge. If u cannot find one, simply redirect your users to ur english sites by placing ur own ads, if they donot understand english, use appropriate image links to redirect ur users.
As formally stated in the following discussion, it is not against the TOS to display Adsense ads on sites with unsupported languages. http://www.webmasterworld.com/forum89/8256-1-10.htm So this is what you need to do: 1. register with adsense for an english website. 2. program your site using UTF-8 encoding. if you dont know what that means, google it. adsense has the capability to understand arabic only if you use UTF-8 encoding on your website. if you don't you'll just get that public service ads. 3. input your adsense code (dont modify the code, just switch your site to UTF-8 encoding) 4. the ads will be justified to the left because the language is not yet supported but hell, at least you got them up there. 5. start promoting your site and enjoy. P.S. Hope this helps buddy!
I am not sure why the ads are not supported in Arabic. There is a significant Arab population and they are very affluent too.