This is a site of one of my favorite mindfulness meditation (vipassana) teacher, Mitra. This is the simplest of all the ones I'm linking you too, and I'd start here. She said she'll be putting more up on her site, it's pretty new for her and a work in progress. Amazing teacher!
www.aram3.com
Here are some really good introductory guided meditations from the Mindful Awareness Research Center I'm a part of at UCLA. I suggest using these to get a really good introductory overview of what guided meditations of quality are like and what they can offer. Diana Winston is a world renowned, fantastic mindful meditation teacher and really a pioneer in the emerging mindfulness meditation professional movement:
http://marc.ucla.edu/body.cfm?id=22
Here are some good guided meditations from InsightLA. These aren't my favorite - actually I'm not a big fan of InsightLA. But they're a fantastic resource and very accessible to. Not quite as good IMHO as MARC's resources, but top notch nonetheless. Great introductory material covering a wide range of subjects:
http://inside.insightla.org/christianewolf/audio-guided-meditations/
There are a lot of other great free guided meditations out there, although keep in mind the actual type of meditation we're talking about here is vipassana, or insight meditation in english. There are many different types of meditation from many different cultures, philosophies and religions. When most people hear the word meditation these days they think of it in a Buddhist context, and in particular they think of transcendental meditation/TM which got really popular in the 60-80's in the West, and is still probably the most popular and the best known (at least on a very superficial level). TM is a very different, particular type of meditation. While very useful, TM is much more narrowly focused and more limited than vipassana, especially when it comes to the kind of work we need to do in our recovery. When I speak of meditation I'm referring to insight meditation or vipassana.
If you have any questions on meditations or mindfulness feel free to PM me. I'm working on a Mindfulness and Meditation sticky type thread for SL, but I probably won't be able to finish putting it together until next week. It will have a lot of free, quality guided meditations as well as a lot of instruction, theory and practical advice on meditation (particularly insight meditation, or vipassana, and lovingkindness meditation, or metta (vipassana and metta are Pali words) - these two types of meditation are really the heart of effective mindfulness/meditation practice, especially when applied and as useful for recovery related subjects and material). Really looking forward to the completed project. Gonna be a great addiction to SL, and I'm really looking forward to sharing what I have with people I love here.