Very hard to turn steering wheel

Heavy steering (not caused by neglected low tyre pressures) is usually related to a problem or failure with the power steering pump system.
Items to check on the Power Steering (PS) System
1. Is the serpentine belt slipping on the power steering pump pulley because it is old and worn and needs to be replaced? If it is slipping it will likely be slipping on other pulleys also.

2. You have allowed the power steering fluid to run low and the PS pump is starved and is sucking air. Running the fluid low will damage the PS pump and the steering rack. Low fluid in the PS reservoir is normally a sign of a fluid leak in the system. A leak could be on a system hose, in the PS pump or in the steering rack.

3. The PS pump may have failed, hence cannot produce the required pressure in the PS system, and needs to be replaced.

Check the power steering fluid level and add fluid if it is low. Check to see if the steering rack is leaking. You can check it by removing the tie rod boots to see if fluid comes out. Make sure the belt is tight. If the pump works and no leaks, you may need steering rack replacement. If you do need to replace your Steering Rack, this site looks like it has cheap prices, free shipping and great reviews http://www.buyautoparts.com/power-steering-rack.html

check th ps pump for a fault

I'm going to agree with the rack conclusion. Keep in mind I can't see it for myself.
If you take the load off the front wheels, you should be able to turn the steering wheel without effort.
If the effort changes while turning the wheel, the only things affected would be the rack and the column.
If you notice it turns ok with the engine off but not with the engine running, it could be something with the pump or one of the lines, or still something with the rack.

Is there any service done on the power steering on the last few days?
Example: replacing high and low pressure hose(s).Leaking power steering rack?
Please place a cardboard on the ground (under the path of all steering components to inspect for leak(s).
It can be multiple spots.Inspect both tie rods for smooth end to end turning operation.(two persons task)
Check power steering for lock up or belt hopping condition.
THESE ARE VERY IMPORTANT STEPS! Mis-diagnosis can cause you $1200 or more.
The most like trouble location (about to leak or burst) is the high pressure hose after the PS pump or between the PS fluid tank.
Check for deform hoses.
The "hard to turn" condition is cause by air pocket / air bubble inside the steering rack.
Worst case is metal fragment inside the rack.
If your 2001 steering is stock and has over ~160,000 miles then you should save up money for a rack + hoses + pump + belt replacement.

sounds like a bad wheel bearing.

this can be the pump or the rack and pinion there is a silnoid in the rack that can go bad cause this problem

Hi! The pulley could be worn or the belt is not properly adjusted.Causing the belt not to grip the pulley but slide on it,creating a friction.

check that the return lines on the steering rack are not blocked.
And make sure the Drive belt for the pump is tight.

Is the belt on the power steering pump tight or loose does the pump makes a huming noise when turning steering all these are causes of hard to turn steering belt need to be (tight) on pump and pump must not be huming when turning steering add fluid if needed and play with steering to see if help if not need to replace pump