Noticed today after a wash cycle that our Maytag washer had sprayed oil on the floor underneath. It has also sounded very loud, almost like a jet engine taking off during the spin cycle.

Yes unfortunately. but it's not terribly difficult to do. There are many how-to videos online

bearings very suspect

bad counter weights, bad damper pads, bearings?

May have a piece of cloth, plastic etc that may be stuck on something between the belt and the drive system, have a look underneath/back to see if anything is there.

It is so common that the drain leaks in many ways and is the most problematic fault in a washing machine. In all occasions it is important that your observation is most important and so is vital to the identification /rectification and solution. If you have noticed that water has leaked then as the drain hose pump/valve and fittings are located on the underside of the machine it is important that you look for possible leaks here. In some cases the drain hose would be clogged at the drain end to outlet of the house and so there will be back flushing resulting in overflow to the outside. Also the drain pump/valve can be clogged or the drain hose clamps can be loose on the grip which can all cause the leak to occur. Removing and cleaning the drain pump/valve, tightening of the hose is also very important. Also water can leak if there are gaps on the front door gaskets and must be checked but this will happen only during the cycle and not on the drain cycle end.

Tips for leak: http://www.espares.co.uk/advice/washing-machines/a/7/1461/do-you-have-a-leaky-washing-machine.html

Check for tips on the link below to identify parts and removal:

http://www.espares.co.uk/advice/washing-machines/a/7

Also check on the SEAL on the door and drum, it can also be worn out and reposition the drum to move out which can result in the noise when the spin is activated.

what kind of noise is it? may need to check the tub and transmission bearings and the transmission spring, and last bad counter weights

The problem is that the seals are leaking and allowing water to attack the tub bearings.
You need new tub seals and bearings.....not as difficult as it may seem.
see u tube video on replacing maytag seals and bearings
Cheers Stan

you have described the noise from a front load washer in the spin cycle to a "T", it definately does sound like a jet engine. if it ain't broke...don't fix it!!

if it sounds like a boeing jet, you will need a new seal & bearing kit. This is something a technician would have to do. many "special" spanner wrenches and spring tools required

Need to know a little more info. Need to know if this noise starts when you first turn it on (during the fill up cycle), once the actual washer starts (wash cycle) or when it goes into spin cycle.