I have been running in a pair of Vibrams for over two years now and it is a great shoe to use and alternate with another pair of trainers. They are also very comfortable to walk in. Although these shoes have their benefit, they are new and unlike most other shoes are designed to mimic being barefoot. Something we generally are not used to.
It takes at least 3-4 weeks to fully transition into a pair of minimalist running shoes. They could be Vibram or anyone of the other zero drop shoes floating around, fact remains you should not just continue with your training like nothing has changed when you get a pair.
The number one thing you want to change is weekly mileage. If it is your first time running in zero drop shoes start by doing a 5 minute run, three times a week. Then add 5 minutes to each run the following week and after that 5 minutes again. By the end of the month you should be on three, 20 minute runs a week. This might sound like nothing for your fitness level and it probably is, but just be patient. It will be a lot harder to not run at all due to injury than to just transition into them slowly. Maybe spend some time riding your bike. Cycling is a great way to maintain fitness and I recommend it to all runners out there.
Many people buy a pair of Vibrams with the hope of changing their foot strike. Let me make it clear that you DO NOT need a pair of Vibrams to do this. You could do it right now in whatever shoe you've got. Go outside and try it then come back and tell me I was right.
If you want to change your foot strike then I strongly recommend you add some form drills (there are many of these online) before your run. These runs that you do with a new foot strike should be treated the same as when you transition into Vibrams. They should be very short and at an easy pace. Remember that there are muscles in your legs that have not done work for ages and are now being called upon.
Lastly, do not make Vibram Five Fingers the only pair of shoes you run in. Alternate them with another pair. I recommend this for any shoe and believe it is important when it comes to injury prevention.