Turkey has several world class players. Tuncay, Altintop, and Arda Turan could play for most teams. I doubt Slovenia or Algeria are on Turkey's level. They didn't qualify for the World Cup but qualifying in Europe is quite a bit more difficult than in CONCACAF. England didn't qualify for Euro 2008 and they are one of the consistent best teams in the world.
I thought it was a good result but in no way will it be indicative of the World Cup. Like vivafutbol said, Spain needed injury time to beat Saudi Arabia and England needed 2 own goals to beat Japan 2-1.