Your chops will come back; you just need to practice.

I really love Francis Ching's books on drawing,and the basic but useful "Drawing On The Right Side of The Brain" and its workbook.

As for me personally, I highly reccommend sitting in on a life-drawing class (I don't know where you are, but Portland has three different life-drawing classes open to the public for a small fee). Or get your friends to pose for you...

Keep your sketches loose and fast. Do ten or so 30-second poses, then do a few 1-minute poses, and keep it that way for a couple weeks. Don't agonize! Be loose!

Yup, it's practice. Knowing how to draw is like knowing how to play an instrument. If you haven't picked up a pen for years you're gonna be rusty.

So hey, warm-up methods that always help me get on a roll and break through those walls of habit.

1) Sit away from object, like a teapot or something and draw it with only one line never lifting the pen.

2) same but with your weak hand.

3) catch people posing (like waiting for a walk sign). You got 30-45 seconds. GO!

4) same but with another tool, brush dipped in ink on moist newsprint paper is great fun. You'll need to get someone to pose for you. Alternativly, use fashion magazine poses.

5) Start a drawing of an object/person from the bottom, move up.

6) If you do some of your comic book panel stuff (which you spend time on unlike the above exersizes that should be a bit quick), always go and look at it in a mirror. The thinsg you missed and any strange perspectives/stuff like that will pop out and bite ya.

See it's not just the hand that needs training, it's the eye.

Specklets right, drawing classes are great though I usually hated the nude posing - but it's cheaper to hit the park and catch other people who sit still for a bit, they read a book, sit on a bench, feed pigeons etc. When park is closed use café.
The only problem with that is that you can bring your giant paper. Get a sketchbook of at least 8*11 inches.

Carry a sketchbook around with you - I have a 9x11ish sketchbook that I carry with me everywhere. Doodle and make short sketches whenever you can.

Make sure that you look at your sketch from different angles - if you're not paying attention, it's easy to sketch something that looks great from the angle you were sitting at, but that looks warped when you look at it straight-on.

Cafes and parks are very good places for sketching someone, since they tend to sit relatively still for a long enough time to let you do a decent job. Also try going to a museum and sketching the sculptures. Those often have fancy lighting that'll let you play with shading and shadows, too.