Pick up your copy of Captain America 25 fast. The New York Daily News has already spoiled the ending, and I’d suspect some other news sources to follow suit. If you really want to know what happens, here’s the article.
Edit: CNN has the story now, too.
It should be noted that Marvel intentionally seeds these stories to hit the day they hit stores to draw people into retail stores. Naturally they want to sell books, but it sucks that surprise endings are often ruined. The problem is that most retailers are small independent stores that have to manage their inventory very tightly. They’ll order enough copies for their regular customers, and then a few extra for walk-ins. Marvel’s been hyping this issue as an important one, so it’s probable that stores knew to over-order it, but chances are it’ll sell out and take a few weeks to restock, ruining the buzz.