I am a noob when it comes to miles. I have started with an AMEX SPG card as it seems to be a great all around card. I am planning a trip to Europe next October and the 50,000 mile Chase United promo has me curious. My goal is to get 2 round trip buisness class tickets for me and the wife. It looks like United, Continental, and US Airways are all part of the Star Alliance Program which I assumer means a mile on one is good for redemption on any.

Does this mean I can apply for the Chase United Promo and get 50,000 United miles. Also apply for the US Airways reward card from Barclays to get the 30,000 mile promo and some time down the line apply for the Chase Continental card and get the 25,000 mile bonus. These 3 cards just in promo miles with limited spending nets 105,000 miles. At that point combine them all together thru Star Alliance and redeem for one business class trip to Europe?? It almost seems to easy if that is the case. If that is right I could have my wife do the same thing and now we have both our tickets and I can use the SPG card for free hotels. Am I missing something or is that pretty much a free trip to Europe??