How can I make a xcel sheet access able to all iOS 5

[imac abuser]

I have a friend that needs to update and store a .xls spreadsheet that can be accessible and writable from his iPad, and iPhone.

Can someone please help me

[bgtrack]

This isn't the right section...but you can use a third party application like dropbox, or you can use documents in the cloud using iTunes...to do that you need numbers on both your iOS device and mac...it won't be excel though