Using TextBox values to generate PostBackUrl

I am trying to create a very simple form with two TextBoxes and a button.  I want the visitor to enter a value into each text box and click the button which should generate a URL and load the new page.
For example if I have TextBox id="sn" and TextBox id="sid" and they enter Kyle as the sn and 12345 as the sid when they hit the button it should redirect them to a new page similar to this:
http://www.anotherpage.com?sn=Kyle&sid=12345
Any help would be greatly appreciated!
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