help on resizing partitions

[xPol]

I would like to resize three consecutive partitions, _without losing 
data_, by shrinking the one in the middle and enlarging the remaining ones.
Is there a clearly readable tutorial about how to do?
I have read, by 'googling' a while, that you have to pay attention to 
'resizing the file system' and 'resizing the partition'. What would be 
the meaning of 'resizing the file system'?

I woudl like to use parted, that is included in my karmic-rescue usb-stick.
Is that a suitable tool?

Thank  you
---P