OK, so I'm really happy with my diet and cardio routine, but I currently have no strength training. I hate gyms , so I bought a set of bodylastics and I'm trying to learn how to use it.

The beginner directions say to do one set of each exercise, and for number of reps per set the book says...

Strength - 6 to 8 reps
Strength and Musculature - 8 to 12 reps
Body Toning - 15 to 18 reps

My goal is to tighten up and create some definition, especially in my abdomen and arms, but not huge muscles or big veins. Which program do I want? I would have said toning, but would that give me more musculature than the musculature program??

I would recommend against the bodylastics. Using weights is a much better source for tracking your progress. If you dislike gyms, I recommend purchasing ChaLean or P90X. Great programs that you can do at home without becoming bulky.

You are not going to bulk up using bodylastics.  If I were you, I'd start doing 6-8 reps for 2 weeks and then up the reps as you get stronger and from there up the resistance.

Also, there are a lot of good strength training dvds out there if you're into that.

I disagree. A lot of people use resistance bands to bulk up. Especially with low rep counts. If you are going to use the bands, do 10-12 reps. But again, I advise against usings the bands, its very difficult to track your progress.

I am not expert.  That said, I am 45 yr old female and I lift free weights at a gym along with doing cardio.  Most girls are not going to get big, bulging muscles because we just don't have enough testosterone.  Mostly I use 10, 12, 15 and 20 pound weights.  That's it. That's just 4 pairs of weights.  I have used the bands as part of a step class, but I think weights make it easier to see how I am doing. 

Weights make me feel stronger.  I love the definition that my muscles have now.  Also weight lifting helps keep your bones stronger too.  So important for us gals as we age.  The guys are always willing to show me proper technique and share their knowledge.