IE. manipulating a (scanned) image. Illustrator isn't even close to be useful for that.
scan and import into photoshop, save file as a tiff or something to that extent, open illustrator and place the scanned image as the bottem layer, lock it, and trace it with the pen tool to get nice crip edges and smooth lines. and you can always copy your paths back to photoshop and use them in either a path or an alpha channel, to color or just out line it.
although illustrator is more print based media so i can see where photoshop comes into play. and no, i didn't misunderstand. and i realize what a tablet does too, but its nothing that the pen tool in either photo or illustrator can't do unless you want pressure sensitive lines.
Illustrator is a cool app. But it can't do what PhotoShop does (and vise versa).
In someways the both do a lot of the same. some of the tools in illustrator 9 are pretty silly like the lasso which they've brought in from photoshop. all it does in illustrator is select points, which the direct selection tool does anyway.
blah blah blah..
im beating this to death, sorry
i do know a lot about what im talking about though! i swear! i'm not entirely knew to graphic design, i'm just on the next level up and im just curious to what other people do for their stuff and why. in the course im taking the guy seems to like all drawing/tracing done in illustrator and then ported to photoshop and now that im using illustrator intensely i starting to like it more than photoshop almost... which is strange because i've been smitten with PS since 4.0... but anyway, i'm overly tired and low on caffeine so i'm going to go look for food/coffee. ciao