File upload problem

Hi,

              I want to upload a file using rails.i am using
file_field and unable to access the input from form(rails view) in
controller, i.e. in parameters it is not sending the file_field input
and it is sending if there are any other type of inputs,except
file_field.

             Can anybody tellme, What datatype exactly file_field
takes and how to upload a file using rails?

            Thanks in advance.

prem.

did you set :multipart => true ?