Found this great, really basic "Anatomy of a Sewing Machine" resource Craftzine published back in April 2007. It was written by Christine Haynes and Kent Bell.
This handy little feature showcased the illustration below, done by Kent, and the corresponding descriptions below. Useful when you're just getting started working with sewing machines as well as when you're troubleshooting.
I was drawn to it because of the graphic (adam thinks I should get a tattoo of it), but upon reading it, found it really really useful. So here it is. Can also be found online here.
1. Pedal - The speed of the machine is controlled by the foot pedal.
2. Slide plate - Slides open to reveal the bobbin.
3. Bobbin - One of the two threads used to make a stitch is stored in the bobbin, which is located under the needle and throat plates.
4. Feed - These little metal teeth pull the fabric through so that it can be stitched.
5. Throat plate - Stays in place while the needle penetrates through a hole to pick up the bobbin thread underneath.
6. Presser foot - Interchangeable with other specialty feet, it holds the fabric in place.
7. Needle - Most projects will utilize one of four types of needles. The sharp point needle is used most often with woven fabrics. The ballpoint needle is ideal for knits; the wedge point needle is used for leather and vinyl; and twin or triple needles are
used for decorative topstitching.
8. Foot pressure dial - Correct foot pressure results in even feeding of the fabric. Some machines automatically adjust tension and pressure to the fabric. Always check tension and pressure on a scrap of fabric before starting to sew. Generally, the lighter the weight of fabric, the lighter the pressure needed.
9. Stitch tension dial - The stitch tension dial sets the amount of tension on the threads while sewing. Too much tension results in too little thread fed into the stitch, causing the fabric to pucker. Too little tension results in a loose stitch.
10. Bobbin winder thread guide - On a machine with an external bobbin winder, the thread loops around this guide between the spool and winder.
11. Stitch selection dial - This is where you choose between the many different stitches: straight, zigzag, and other decorative stitches. Can also be done digitally.
12. Needle position - If you are sewing a zipper or doing other specialty stitching, you might need to move the needle from the center position to a left or right position.
13. Spool pin - Spool of thread sits on the spool pin. Some machines have more than one for decorative stitching.
14. Bobbin winder - The empty bobbin sits on this winder to be threaded. When winding bobbins, always start with an empty bobbin so the thread will wind evenly.
15. Flywheel - This wheel spins as you push down the pedal. Most machines disengage the flywheel when winding bobbins.
16. Stitch length dial - The stitch length dial is on a "per inch" scale from 0 to 20 per inch, a metric scale from 0 to 4mm, or a numerical scale from 0 to 9.
17. Stitch width dial - When you use decorative stitches and zigzag stitching, this dial can determine the width of the stitch.
18. Reverse stitch button - If you want to secure your stitch at the beginning and ending, sew a few stitches in reverse by pushing this button down.