Price difference of 5k. 6230 is no longer manufactured.
There is no difference in the design (except for an improved center click, as earlier center click would cause false firing of the directional keys, and the camera window now says 1.3 Megapixel), or the battery capacity (which is really sad).
Inbuilt Memory:
35.5 MB against 9.3 MB earlier
Display:
208×208 pixels as against 128×128 earlier
One of the sharpest displays due to this extremely high resolution in the tiny screen
Both are 65k active TFT displays
Addition of Push to Talk
USB connection now allows the use of MMC card directly as a USB drive. No need for PC suite or anything, auto detection under Windows 2000 and higher.
Support upto 512 MB MMC cards officially, and 2 GB unofficially.
Radio and MP3 player significantly improved. Radio now has a visual component, which is not yet supported in India, but allows content retrival depending upon what is playing. MP3 player now has the much needs fast forward and rewind options. Playlists can be generated on the fly.
Special headsets allow one or two line display of ID3 tags and other information such as caller id, with upto seven configurable buttons. This headset has to be bought separately, but is not compatible with the 6230. In fact, currently it works only with 6230i amongst all Nokia phones.
Camera
1.3 Megapixel as against 640×480 earlier. Leads to very large images sizes, and considering no increase in processing speeds (33 MHz), can be cumbersome to work with.
Unlimited video and audio recording till the capacity of MMC is exhausted.
General Bluetooth, IR and menu interface improvements. Voice tags for MP3 player now possible.
Both models feature EDGE upto 236.6 kbps.
I guess that is it. Ask if you think I have forgotten something. I really wish I had the i!