i was not able to upload more than 2Mb size

i searched across forum and i came accross this post
"You'll also need to configure your server to accept the file sizes (configuring the max file size in SWFUpload does not configure your server). You should also configure your server to allow the script to run long enough to accept the upload. You should be able to do this in your web.config."

please help me how to specify that in web.config