transfer data from iPad

Transfer what data from which apps ? You should be able to copy iTunes purchases to your computer's iTunes via File >Transfer Purchases. For content that is in third-party apps you will need to see what they support e.g. the file sharing section at the bottom of the device's apps tab when connected to iTunes, via wifi, email, dropbox etc.

You can copy to your computer photos taken with the iPad, copied to it via the camera connection kit or saved form emails/websites : http://support.apple.com/kb/HT4083 . For photos that were originally synced from your computer (so they should still be on your computer and/or on a backp) then there are third-party iPad apps such as Simple Transfer which can be used to copy photos off your iPad via your wifi network. But as photos are 'optimised' when they are synced to the iPad, any that you then copy back to a computer may not be exactly the same as they originally were on your computer.

For music and other purchases from Apple then connect to your computer's iTunes and do File > Transfer Purchases. Music that was purchased from other sites or copied from CDs should already be on your computer (and/or on a backup) as you will have synced them to the iPad from your computer originally - if you don't have copies on your computer then you will need to find a third-party program that can copy them off.

To sync photos to the iPad, connect and select your iPad on the left-hand side of your computer's iTunes, and on the right-hand side there should be a series of tabs, one of which should be Photos - if you select that tab you can then select which photo folders to sync to the iPad. There is a bit more info on this page . You will need to sync all the photos that you want on the iPad together in one go as only the most recent photo sync remains on the iPad - not including photos in a subsequent sync is how you delete them from the iPad.

Similarly music is synced to the iPad via the Music tab : http://support.apple.com/kb/HT1351

If you don't have a copy, then you can download the iPad manual from here : http://support.apple.com/manuals/ipad/

If you an an app on the iPad that supports .xls files e.g. Apple's Numbers app or third-party apps such as Documents To Go and QuickOffice Pro HD (there is no actual Microsoft Excel app) - the iPad doesn't have a file system like a 'normal' computer, everything has to be associated with an app. How you then get the document into the app will depend upon what the app that you get supports e.g. the file sharing section at the bottom of the device's apps tab when connected to iTunes, via wifi, email, dropbox etc.