I'd like some tips on cropping an image from a picture smoothly, without those awful edges and such. I know people can crop an image from a pic and put it on a white background and have it looking smooth edged. Anyone know how?

You can use clips and masks:

Clipping paths: http://screencasters.heathenx.org/episode-033/
do this to get the cut out look.
Masks:
If you don't want the sharp outlines, then fill the clipping path with white and blur the shape a bit. then do Object -> Mask -> Set

Use of masks is likely what you want. Easiest way of learning about masks is to apply Grayscale (Luminous) black/grey/white values to the mask.
black areas will be fully transparent
grey areas will have partial transparency
white areas will have no tranparency

So using a white fill and a black stroke, then blurring the mask will give you the partial transparency (smooth) edge.

You can get some nice free masks from the website below.
http://graphicssoft.about.com/od/freedo ... esmain.htm

http://tavmjong.free.fr/INKSCAPE/MANUAL ... sking.html