QTP 10 does not support Mozilla 8.0 and Chrome browsers
If you install "Utilu"(Tool to use multiple IE browsers(From IE 1 to IE 8)) at a time, say for example if user wants to run automamtion script on IE 7 then we can configure this browser in our environnment variable (QTP) by this way we can confgigure depends on the user input.
Note: QTP 11 supports Mozilla Browser.
Please refer this url for quick reference utilu.com/IECollection/
Regarding the framework creation,
It depends on your project requiremnt.
First try to get some idea on below factors, i.e.
Whether your projects is Test Data maintatinence or Script maintainence.
Whether it is a data driven testing approach or not
Whether it is a resuable scenario approach.
Start thinking on above three, so that you will keep on asking your self many questions related to Frame work
Frame work means how the way you are restricting yourself by following coding standards.
Please let me know if you need more information apart from the above.