I had been asked for help on to hand trace some of these images using Adobe illustrator, so I figured it couldn't hurt to take some print screens of my steps and to explain each step out. Im using Adobe Illustrator CS2, but most steps will work in older versions too. Im sorry if this is long, but hopefully it will help. So here we go.
Step 1: Open picture into Illustrator, highlight picture, and click on the Object tab and select Lock Object, then click on Selection.
Start with the Pencil Tool and start to trace the lines in the graphic. Adjust the stroke weight that will match the lines of the picture best. You can also use the Wrap Tool to assist in making smoother curves.
I leave large open areas that will be the same color as the lines im tracing alone until the end. When tracing the graphic, change the stroke weight of your lines depending on what matches the original the closest.
After you have finished tracing all of the lines that need to be trace, highlight entire graphic, click on Object Tab, select Expand, hit Ok on dialog box that pops up.
With your trace highlighted, click on Merge to merge all of your objects together.