Characters now get to add one point to an ability score every fourth level. There are six 'standard' races for 3 rd Edition. They are the Dwarf, Elf, Gnome, Halfling, Half-Orc and Human. In reference to the new art for the races, someone has already said there is only one race in 3E - elves. That assessment is a little harsh perhaps, but it does give you an idea of the change in the way the races are depicted.
Gnomes are no longer goofy, big-nosed guys.
Halflings are no longer pot-bellied children, etc. Whether or not you like the new depictions will simply be a matter of personal taste. Racial Traits remain unchanged for the most part. Elves still get a chance to spot secret doors. Dwarves still get a bonus to their Constitution and a penalty to their Charisma.