I am trying to be prepared for the coming up Christmas, and I was wondering if I could use the PWM function on the Arduino and a transistor to fade the lights. Last year I used 8 solid relays and hooked them up 8 plugs to blink the lights.
So my question is if my solid state relays could handle PWM? If not what type of transistor should I use, and how I would set up The transistors? 
Sorry if I misspelled any words I am a very bad writer.
What is the voltage and current of the lights you are controlling?
post a data sheet for the SSR. that wil list speed of response.
also need to know what type of lights. simple resistor based LED's or incandescant and you can PWM them to dim them. some LED's are serial based control those you control with the arduino directly.
The data sheet for the 8 solid relays are right here:
http://www.songle.com/en/pdf/20084141716341001.pdf
The LEDs I am using are just regular Christmas lights.
Those are not solid state relays they are normal mechanical ones.
No you can not PWM a solid state relay unless it is a special DC SSR and you can't control anything mains powered with it.
To fade mains powered lights you need phase angle control.
Seems you were switching the mains power of the LEDs.
Can you post a picture of the label on the LED power supply.
Leo..
Would it work if i did this than?
Would it work if i did this than?
Well it does say instructables in the URL so that is a caution. However you need to know the circuit of your LEDs before you can say if it will work.
I am going to wire the Arduino controlled light dimmer to a plug and dim the power of the plug, so I can yous the dimmer to dim other things other than the Christmas lights. Like for ex. a lamp.
If your lights already contain a dimmer or a switch mode regulator then you will not be able to dim it with any circuit. You need to know what exactly you are dimming.
No, the lights I will not be using a dimmer or a switch mode regulator.
So we know what you are NOT using, but we still don't know WHAT you're using.
Leo..
Sory i have not replied for a while, I have been fealing sick. 
But the lights i am using are similar to this.
http://www.amazon.com/Indoor-Outdoor-Christmas-String-Lights/dp/B00PJCVI8M
Last year i put lots of those over my house and made them blink with the relays. I liked the way they looked but i wanted this year to be beater. That's why i want the lights to be able to fade.
They seem to be incandescent lights.
But the add says nothing about power source. Just "a plug at both ends".
Not even a picture of it.
So again. How are they powered.
Just a plug at the end, or a power brick.
Leo..
I did something very similar to this:http://www.instructables.com/id/Arduilay/?ALLSTEPS
But it still follows the same concept.
