Were you / are you bad with math at School? 2.4GHz means 2.40GHz, not 2.04GHz. 2.26GHz can be considered 2.2 GHz or 2.3GHz depending if the person wants to make numbers look better
And the MacBook has a 2.26GHz and the MacBook Pro a 2.26GHz too the single difference (hardware wise) is the HDD, the MacBook Pro has a smaller 160GB vs the White MacBook's 250GB, that's just because the MacBook Pro is outdated.
The MacBook Pro screen also has a 60% Better color gamut, SD card slot, Firewire, Battery indicator, backlit keyboard and a better body, the MBP has no heating problems, nor the White MacBook, that just happened to older generations.
If i were you I'd wait for the new MacBook Pro, if you can't wait, still get the MacBook Pro, i think that just those features like the better body makes it worth it the extra 200$