Outside to in downswing promotes a fade.  Inside to out downswing promotes a draw.

Strong grip promotes draw.  Weak grip promotes fade.

Ball back in stance promotes draw.  Ball forward promotes fade.

Standing flatter promotes draw.  Standing taller promotes fade.

Check your setup first.

Several things come to mind and any one of these or a combination can cause you to hit a fade. Shoulders slightly open even though feet are square to the target line. Ball played back slightly from normal position. Taking the club too far inside on back swing can make you come down across the target line (over the top or casting) FROM OUTSIDE TO IN instead of inside to out. Grip got a little weak without you noticing it. Make sure you can see at least two knuckles on your left hand when you take your grip (this is for a right handed player). My bet is it is one of these.

One of the volunteers at www.allexperts.com mentioned that a flat front foot at finish can also cause an open clubface.

The handle too far ahead of the ball causes an open clubface if the ball is back in the stance.

There are a gazillion things but "over the top",  outside-in downswing, or weak grip are the primary culprits.

Lou, I learned something from Golf's "Best Driving Book Ever". The anti-right and anti-left shot. If you positively do not want to drive the ball right, then move the ball up slightly from it's normal position. This will promote a down the 3'rd base line hit. Don't want to go left. Move ball back from normal position and this will promote a down the 1'rst base line hit. Also with modern drivers that have longer shaft lengths, tee the ball up off your big toe and not off your arch or heel of your left foot (right hand hitters). Back when I was a kid ( a gazillion years ago) the driver shaft was 43 inches and teeing up the ball off your mid-arch/heel area was taught. Today's drivers are 44 1/2 -46 inches and you need to tee it up off your toe. I tried it and it works great.

I remember those drivers because I started playing in 1972.  Also, persimmon 3 woods were only 42" back then and much easier to hit vs the modern ones.  I actually could hit a 3 wood much farther and lower than a driver back then and have hit a couple 300+ yarders.  I have established a shaft length of 41.5" for my 5/7 wood (I no longer carry a 3 wood because I hit an 18* fairway just as far and there is only 5 yards between that and a 20* fairway).   I also used to remember they taught people to address the ball with the hands way ahead and look out the corner of the left eye.   Modern golf instruction teaches us to keep our heads behind the ball and hit up. Old golf instruction also taught us to have half the ball above the crown of the driver and modern instruction has the bottom of the ball even with the crown.   My tee height is such that half the ball is above the crown (tee height is about midway between 1st and 2nd knuckle of index finger).   AND I hit slightly up - I would hit a moon ball if I teed it up as high as some do.

I found out quickly in 2007 that a 44.5" driver is perfect.  My dad gave me a X Speed w/ ProForce ATR stiff that I used alternatively with a 975D for a year.  I played with a G2 driver between 2008-2010.  These were all 10.5* neutral drivers and I got much better distance and lower trajectory with a power fade vs a dead straight shot. 

I've got Jim McClean's "The Three Scoring Clubs" and there are a lot of good tips.  The only thing is he promotes the big 90 degree "parallel at the top" swing; however, he has a series of checkpoints.   He does recommend a driver of 44-44.5" for most golfers.

Two sets of videos have helped my driving.  It started with Don Trahan "the Swing Surgeon".  He is one of the biggest opponents of the "rotational" golf swing because of the back problems it can cause.   He also recommends a shorter driver (43.5 - 44") for better control.  I found out about Paul Wilson (who has a series of anti-slice videos) at Peak Performance Golf System (now called Revolution Golf) when looking for DT's videos (he now has his own website www.swingsurgeon.com).  Basic bottom line is that both promote a compact backswing.  Paul's main philosophy is the reason people slice is because they swing too hard (causing the arms to take over and an "over the top" motion).

I would say I play my ball off the instep of my left foot.  Because my foot is slightly open, that puts it inside my ankle bone.  In regards to ball position, in relation to the torso your head is slightly behind it and it lines up with your shirt pocket.  There is also another thing about ball position - if it isn't correct, your hands are going to fight you during the swing (for instance, you have an overly strong grip if the ball is too far back).

Have you started teeing the ball higher so you can swing up on it more?

It is true that too low of a tee height promotes a fade. 

I've found between the first and 2nd knuckle of the index finger for tee height is good for me.  I hit the ball solid that way.  With it at the 2nd knuckle, I hit too high of a trajectory and lose distance.  If you look at a lot of the pros, the most they may tee it up is about 2".

Gus,

Maybe your swing plane got a little steeper.  Try sticking out your rear-end a little more and make sure the club approaches the ball from the inside.  

We don't want steep, we don't want flat.  We want a swing plane that is right in between.  

CH

Exactly.  Athletic stance with a reasonable amount of knee flex.  Arms hanging down and extended slightly.