No worries...
There are LOTS of ways to isolate a particular colour from the rest, it very much depends on the image as to which one you use.
In the example we've been using I set the Magic Wand 'Tolerance' to 10 but you may find increasing that will remove more of the 'white'.
The danger there though is that it may be OK in some places but not in others, you have to adjust for the best you can get and then manually fine tune it.....PS is good but it can't get everything spot on every time, its just the nature of digital images.
If you change the 'Tolerance' setting and try again you'll see that the marquee changes accordingly....change it drastically to see exactly what it is doing...you can always use Ctrl + D to remove the marquee, change the tolerance and try again....repeat until you think you've got 'most' of the white.
After that, zoom in so you can see what you're doing and manually Add to the marquee with the lasso, or polygon, or rectangle, or elliptical tools OR subtract from the marquee....Use 'Alt' instead of 'Shift'.
If you are feeling confident enough you can try 'Refine Edge'....you'll see the button at the top of the workspace whenever a 'marquee' tool is selected.
This is exactly for the purpose you describe although it does take some practice to get it just right.
If you decide to give it a go you could do worse than watch a few videos on 'Refine Edge', you may even find one for CS3 but if not, later versions use the same principles...you'll just have to adapt to your version.
Good luck.
Regards.
MrTom.