Installing IIS

I am new in .net platform. Currently i have followed the tutorials on how to download IIs and everythin.Once i have done all the installation and when i want to test whether my IIS workin or nt, i have typed http://localhost in my browser.The browser then askin for username and password for the localhost.Actually what is that and how to i overcome this problem.Plz help me and send me an email to vij_pat2003@yahoo.com.If nt also plz reply this thread.i desperately need an answer.thank you

Thank you.