I am taking beginner Salsa Dancing classes. And my instructor always says to find the beat before I start my dance steps. He listens to the music and counts 1-2-3 5-6-7. And once he starts counting I can get my steps right and I can do the basic salsa steps in the 1-2-3 5-6-7 time frame. But when he's not counting aloud, I can't really find the the beat on my own and I just dancing without waiting for the one 1.
In the music there is so much going on. What is my instructor listening for when he picks up the count? Is he listening to the bass or the drums? There some to be a multitude of percussion instruments in the music and I have no idea what to listen for to find the beat. He always points out the "double beat", saying that thats one. But I can't really hear a double beat or know what a double beat is for that matter.
And just to be clear, I don't know anything about music theory on anything like that 
Does any one have any words of wisdom?
Finding the beat is always the hardest part as a beginner. Salsa music is syncopated so the music doesn't always emphasise the beat in the way most Europeans and North Americans are used to.
The fastest way is to listen day and night and eventually it will sink in. Even when you can find the beat, listening to the music a lot will improve your dancing as you learn to interpret the music with your dance moves.
Normally you can hear the cowbell on the 1 and the 3. Since you haven't mentioned anything else I assume you are learning to dance on1. In that case listen for the cowbell.
The clave is the root of all salsa music and it is a great way to find the beat too, but often you really can't hear it well among all the instruments except in traditional son or rumba. The "1" of the clave is on the 1 and the "3" of the clave is on the 4 (good for dancing contratiempo, i.e on 2,3,4 6,7,8)
The clave you will hear in music from New York, Puerto Rico, Colombia and Venezuela is son clave. The link below plays a basic son clave. 1-2-3 1-2
http://www.timba.com/artists/charangahabanera/mp3/ClDeb/cd_audio_03.m3u
Cuban salsa uses a lot of clave from afro-cuban rumba so you will probably hear more rumba clave than son clave, but both are present. In this case there is a slight delay on the "3-side" of the clave. the third strike falls on 4 and half rather than 4 so people often confuse the 2-side and 3-side of the rumba clave here is an example of 3:2 rumba clave. It sounds like the first 2 hits go together and the last three but actually it is still 1-2-3 1-2
http://www.timba.com/artists/charangahabanera/mp3/ClDeb/cd_audio_04.m3u
When you have time to kill in front of the computer watch salsa dance videos and try to see if you can see how the feet match the ryhthm, but mostly listen and dance and listen and dance and listen and dance and eventually it will sink in. Practice makes perfect. So practice outside of salsa class. Find someone else in the class who wants to practice and work on it together.
I prefer dancing Cuban Style salsa so I don't know much about good links to "regular" salsa dancing but here is a good one for Cuban dancing. The point of this is not the moves (cubans rotate when they dance, they don't dane insa straight line) but watch how as the music changes, like when the heavy synth comes in and the percussion drops out, they change what they are doing. They either dance afro-cuabn rumba or tembleque (trembling) and then go back to turn patterns. When you have listened and listened and listened to the music you will also "feel" the changes in the music and your interpretation of the dance will get better
http://youtube.com/watch?v=-30RzT2wn64
