i want to establish Android in our company. Since our company doesn't want our future internal Android Apps distributet to the Google Android Market i would need to setup an internal market. But i can't find any resources. Maybe someone here knows more!
There's not a way to get an "internal" market like Android has, however there are a few options that you have assuming that your users go into settings and select to allow applications from unknown sources (non-market apps).
web market - Create a mobile site where users can browse your applications and then download the .apk files. Once downloaded they can just select them to install the application on their device.
App market - Create an Android app that acts as a marketplace. It can use services to query your app repository and allow users to browse, install and update your applications from that app. This would be more work in keeping things in-sync than just a website, but would ultimately be the best experience for your users. The only thing you would need to do is figure out how to get them to install this app (see 1.)
I agree with Ryan's answer unless you have users on AT&T (Or any other carrier that prevents non Android Market apps from being installed on the phone).
In the case of AT&T, you will need to side load the apk using a PC utility that will require the user to download the apk to the PC and then install the app over USB.
So you might want to make your internal web market viewable by PC browsers and make the apks downloadable to the PC desktop. If you have AT&T users in your company.