Well, there are many ways to bend a cylinder. One good one is this:
1) Use the curve modifier. This is how to: Add a curve by going to add > curve > any it doesn't matter what curve you add. Select the cylinder, and go to edit mode. CTRL+R, and before selecting anything, scroll your mouse wheel so that it adds around 100-200 loop cuts around the circumference.
Now, you can adjust your curve any way in edit mode too, for it will be the basis for the deformation of the cylinder. Select the cylinder once you are done, and add a curve modifier. Set the deform curve to your curve, and move the cylinder so that it is positioned around the curve. It should be deforming currently. If you want it to keep that position forever, then apply the modifier. If you want to animate it, then don't. Here's a picture of a nicely curved cylinder using curve modifier: