code on first page from where you are using querysting
String strVal1 = "My first value"
String strVal2= "My Second Value"
String strUrl= String.Format("default2.aspx?{0}&{1}", Server.UrlEncode(strVal1), Server.UrlEncode(strVal2))
Response.Redirect(strUrl)
code on the second page to get querystring value
String strQueryVal1=Server.UrlDecode(Request.QueryString"strVal1"))
String strQueryVal2= Server.UrlDecode(Request.QueryString("strVal2"))
This will be very helpfull when you have some string value like " Home & Office". In this exaple if you use simply query string to pass the value then you will get the value in output as "Home Office".
try it. :)