if you consider the features, nokia 6230i is far better than 6630
6230i has 32mb internal memory, non-symbian (which means no viruses).
the only disadvantage is the comparatively smaller screen size.
6630 on the other hand has symbian, 8mb internal memory, wider screen.
EDGE, 1.3megapixel cam etc are common to both.
both include other standard features such as GPRS, bluetooth etc.