I bought a ticket for Alaska airlines through expedia earlier today, but just noticed that in my traveler and cost summary it says my first name, but then repeats my last name twice. Like John Smith Smith. Will this be a problem when I try and fly in a few days? Any help would be nice, thanks!

No it wont be a problem.
To be safe, I would call the airline and let them know. They will either correct it, or just note the record of error so you wont have issues.

In recent years, the airlines have gotten alot more flexible on name issues. Post 911 they were bumping people for very minor name errors, but today not so much.

I am travel agent, and always say to people that if they are worried about anything associtated to their travel, the best advice is just to get out to the airport a little more early. Even if there was an issue, you will have ample time to correct it.