Check out IronMind.com - they specialize in forearm and grip strength. 

There are really two issues here, muscular strength of the hands and forearms, and also joint strength.  The muscular strength will grow as you do the work, but by doing exercises to increase that strength independently, you may accelerate your overall progress.

Joint strength is another matter. I have extremely slender bone structure, so when my bench started to exceed my bodyweight, for example, I could feel the wrist joints grinding whenever I hefted the weight.  Very painful and scary - I was honestly afraid that I would break them, which would cause me to drop the bar, which isn't good.  Ditto for barbell curls - my wrists would swell up and ache - bone ache - for days after a workout. 

In my experience, the joint strength will increase with time, but it's a slower process than increasing muscular strength.  So I settled on a weight I could do without injuring my joints, and just increased reps and sets instead of weight, until the joints could handle more weight load.  Where bones and joints are concerned, pain is a bad thing, and should be avoided.  If a weight pains your joints, lower it, or the best case scenario is you wind up in physical therapy ten years down the line.  Worst case is joint replacement surgery, which happens to a lot of serious weightlifters who overdo it or don't watch their form.

There's a really good guy who's involved in our little community who, the last time I spoke with him, was getting ready for double shoulder joint replacement.  He's a former competitive weightlifter.  Joint replacement is no kind of fun. 

I think the physiological process of bones getting stronger is called "bone modeling", and I recall Krista has written about it.  Any doctors, med students or other pros want to take a crack at this?  We know you're out there.

My's main Sifu was my's maternal Grandfather and he always said that without strong joints and bones everthing else is useless because they do not have the foundations to support them. He believed that a person with superior joint and tendon strength can conquer even the most muscular person because the joints of the muscular person are fundementally weak and cannot withstand vast ammounts of stress or strain.
He was always proved right in the matter when drawn into deadly combat.
My's Grandfather was a strong believer in Foundations of things. Saying that nothing can be built without them. From buildings to techniques to even your own Soul. All begins with a strong foundation and good materials to build upon them.
I's owe so much to him and it is good to recall the lesson he once did teach.
I's have many of his words written in long misplaced books and journals. Since time is now more abundant, I's may attempt to rediscover them and revisit his wisdom -even though I's will have to translate from my's basic Chinese script.
Thank you, dear Victor, for the prompting of such memories.
Peace
The Pimp NeonBlack