accessing query string value

Hi....
Im jus a begnier ov aps.net....
im having the following problem
i have a file named print.aspx. There is a link over the print file named friendly print. Behind the link i coded as <a href="print.aspx?mode=print">
As u can c that whent the link is clicked it is redirected to the same page. I want to retrive the querysting value and want to give the if statement like:
if (print==mode) then
{<link href="style1.css" rel="stylesheet"/>}
else
{<link href="style2.css" rel="stylesheet"/>}
hope so u understand that what i want to do. Please help me out
...