Depends on you.  If you have pretty decent mechanical skills, it's not hard at all. 
 
0. Drain oil and coolant
1. Pull the plugs and wires out.
2. Disconnect all the harnesses attached around the head
3. If you're reusing the timing belt make marks on the cams and on the belt
4. Pull off the valve cover
5. Remove the camshafts
6. Remove the head bolts in sequence
7. Take off old gasket, and clean the area removing all grime and old gasket material.

To install just do it in reverse order.  Good luck with timing, if you're unsure of the timing have it towed to a shop.  The towing and timing will still cost less than having them do it all.  As for time it takes me for the install its less than a half hour to do it.

I posted that from memory so if I missed something someone correct me.  Also Serg, don't force anything, if something seems stuck hop on here and ask for help.

Mhardiman, how expensive do you think that job would be?

You'll wanna check the head bolts.  It would be a waste of time to do all that work and put bad head bolts back in.  In order to check the bolts, hold a straight edge up to the threads of each bolt and make sure that all threads touch.  If there is a gap between the threads and the straight edge anywhere, then you need new head bolts.  You can get a new set for $20.

When installing the head bolts, put some oil on the threads of each bolt to ensure correct torque measurements.

Start with the 6 long bolts:
First with the middle bolt on the exhaust side and torque to 25 ft/lbs.
Then the middle bolt on the intake side.  Also 25ft/lbs.
The the bolt immediately right (towards trans) of that one.  25ft/lbs.
Then the bolt immediately right of the first bolt.  25 ft/lbs.
Then the bolt immediately left of the first bolt.  25 ft/lbs.
Then the one straight across from that on the intake side.  25 ft/lbs.

The short bolts:
Start with the one to the far right on the intake side.  Torque to 20 ft/lbs.
Then the one straight across from that on the exhaust side.  20 ft/lbs.
Then the far left bolt on the exhaust side.  20 ft/lbs.
Then the one straight across from that on the intake side.  20 ft/lbs.

Back to the long bolts:
In the same order as above, re-torque the six bolts to 48 ft/lbs.

Short bolts:
In order, torque to 20 ft/lbs.

Long bolts:
In order, torque to 50 ft/lbs.

Short bolts:
In order, torque to 20 ft/lbs.

Now in order tighten all ten bolts an additional 1/4 turn (90 degrees).

 

There are different ways to do it.  You can mark the belt on top of the two camshafts (right in the center) and mark the camshafts right below it with a grease pencil.  Then pull off the camshafts and let the belt slide off.  To put it back on, just slide the camshaft back in place matching up the marks.  This way is a little risky, because you have to make sure the crank doesn't move.  It's quicker and if you do it right, it'll be fine.  But our engines are interference which means that if you're timing's off you're looking at wrecking your valves and possibly pistons.

The other way is to cut the belt, and remove the head.  To put it back on, you have to line up the marks on the crank, to the mark on the block they're little triangles.  Then there are marks on the camshafts, they also have little triangles on them.  Point them at each other.  Then the tensioner needs to be removed and compressed.  Insert a pin of some sort (i used a small allen wrench) to keep it compressed, and put the tensioner back on.  Now take the belt and put it back on crank first, around the water pump, up to the front cam, then the back cam and back down.  Make sure all of your slack is on the rear of the engine.  So when you release the tensioner all your slack tightens up.  Then move the crank by hand three full revolutions.  If the marks are good, then you're fine.  If stuff doesn't add up you have to do it again. 

If you're worried or don't want to deal with the headache.  Do the head gasket stuff, and then have it towed to a shop.  Let them deal with the tedious crap.