i want to start scanning and digitzing my old photos so I can sort
them, print them in photo books and on cds (using my new powerbook mac
laptop).  I have a scanner/printer flatbed with  1200X 2400 dpi
optical resolution and 48 bit color depth.  (I do not want to print
them out on this scanner/prnter but just digitize.  I want to know if
this quality is good enough.  i don't want to have to redo this
scanning later on down the road.  Also I do not want to ever print
this out on a professional photo printer larger than 8x 10.

Here is a nice online calculator:

http://www.scantips.com/calc.html

I'm currently in the middle of doing this myself. It's such a pain to
do, but I'm hoping it'll be worth it in the end.

I don't really have much knowledge on the subject, but here's what I'm
doing: I'm using Dell's Photo All-In-One Printer 922 with a Flatbed
scanner; 600 ppi scanner optical resolution and 1200 x 4800 dpi
maximum printer resolution. I'm scanning at 600dpi using the .tff
format. This makes for very large files, but the quality seems to be
just as good as the original, if not better (I know, not possible). So
far I've scanned just under 1000 photos and it's taking up about 6 GB
of space on my laptop. I have a dedicated laptop for this project so
file size isnt a concern for me. Like I said, I really don't know what
I'm doing; I just messed around with the settings until I landed on
these. The prints look great. - artqs

thanks canadianhlper & artqs...
artqs isn't jpeg a better format for higher quality photos?  or do you know?

Nyma...

If there is ANY chance that you may edit the pictures in the future I
would recomment .tiff format as it does not introduce artifacts or
loss of info when making edits and multiple saves.

.tiff may take much more space put it will preserve the picture to
exactly what you scanned.

Wiki has some good info here:
http://en.wikipedia.org/wiki/Image_file_formats

Yes, I agree with canadianhelper completely about .tiff files. They
will be much larger, but the files themselves will be exactly as you
scan them.

 - artqs

Here's a short guide.
For a color photo to be printed magazine quality in an actual
magazine, the resolution should be 266 to 300 pixels per inch. For an
inkjet output, a 150 pixel per inch photo will look just as good as a
300 pixel per inch.

Now... how big do you think you'll ever want to print your images?
Multiply the linear size by one of the numbers above and you'll get
the optimum resolution.

And, yes, once you've scanned the image save it as a TIFF!