MS-Excel Interview questions

Hi,

I am working as a recruiter and i need to work a lot with spreadsheets and junk of data. i have to use excel to sort and other activities and use filter and other functions.At times iam required to write macros too.But the problem is i don know excel to that extend.

I need expert advice from you people that where can i find in web this details about excel and its all features and interview querstions about ms-excel.

Looking forward for your help.