I think you could have a look at this apple doucment:Installing apps wirelessly
With this doucment,you could creat a ad-hoc ipa,and upload to your server, people coule install the ipa via safari.
(Btw:其实你可以看这篇文章,里面有一个demo的链接,虽然这个demo上面的ipa需要越狱才能安装,仅仅是给你看一下效果。如果你有加入udid或者用企业证书打包,那就没有限制了,无需越狱)