There sure is! i rememeber lines were a ----- to colour until i found out how to do this: (P.s, is helps if u have already done the drawing in black outline pen)
In photoshop-
1) Switch the mode from RBG to CYMK
2) Click n channnel (if u can see them go to window, show channel)
3) Highlight the black channel only
4) press the load channel as a selection button thats in at the bottom of the same box
5) Edit-copy
6)create a new channel, call it linework or something anf highlight it
7) Edit Paste
8) click on CYMK and the the eye button next to the linework channel and voila! u can colour over your lines without having to work around them
The problem is though that once you have finished colouring, u have to put the lines back ontop of the colour (confused? lol sorry, once u finish colouring i'll tell u how to do that)
With shading there are two main ways u can do it, using the dodge/burn tool (the thing that either looks like a hand or a black lollipop) these can lighten or darken areas of colour, however i've been told by comic colourists that its the cheats way of doing things (doh!)
What they do is use the airbrush tool to add sources of light or reflected light. Then the use the lasso tool, followed by the gradient tool to add highlights (gives the picture a shiny liquidy feel, mah favourite

) i can show u how to do that in more detail if u want
it hink photoshop is the better of hte two to colour with, but i'm not sure, cause i've never used paintshop lol!
if u need anymore help just ask