We stayed at Ko Olina in Feb 2008. Other than the resorts, there isn't much nearby; it's kind of separate. In Honolulu, Mandarin is a very good, inexpensive Chinese restaurant; we go there every time we're on Oahu. Alan Moana mall has good, cheap plate lunches in he main atrium area. If you drive to the North Shore (& you should), Giovanni's is a shrimp truck on the North side of the road, near the Polynesian cultural center; cheap, huge plate of scampi & rice (don't be fooled by the look of the truck). Also, on the North Shore, stop at Matsumoto Shave Ice in Halewa, then poke around the shops. We went to the Japanese restaurant at JW Marriott (near Ko Olina) & it was fantastic, but not cheap; go there if you want an upsale night out (it's also a nice walk along the ocean from Ko Olina).