Hey! I just want to share my experience with you on what happened with my Incase Power Slider.
I bought one and followed the directions and used it to charge my phone. The charging of the system only took three hours and it appeard to work fine. I charged my depleted phone on it and it was just heaven, except that the device and my phone heated up and got warm and then hot. When the charge was done, I took my phone off and used it as normal. The next day, my 3G would not work to save my life. I tested it and tested it. My husband's 3G was working and mine would not. I could not even get on the internet using WIFI. Nothing was working. No App store no iTunes, nothing.
So, I went home from work listening to my music not knowing what the friggin deal was. Okay fine, I got home and unplugged my earphones and did some home stuff and then went to make a call, so i plugged my earphones back in. As soon as the plug made contact with the headphone opening, the device emitted a spark.

WTF!! It was a small spark that i likened to maybe too much electricity in the air or something and I actually made my phone call.

Stupid, but I think I was in denial because the spark was nothing to talk about. Kind of like a spark after running your feet over the carpet and touching your dog or your friend. So I thought nothng of it.
I didn't put two and two together blaming the Power Slider at all. At the time, it never dawned on me that the Power Slider had fried the inside of my phone, frying the 3G chip and rendering the phone useless, except for listening to music. I had no idea.
So the next day, the phone completely bugged out!! It was not working properly at all. I got fed up and called Apple and I talked about all the things the phone was doing and then i casually mentioned the spark and I was instantly whisked away to someone else because the call now was escallated. They asked me a series of questions about buring and frying myself and if the phone was melted in some parts and this and that. The phone was not damaged and I didn't think that little spark was a big deal, but the rep did. He said its serious and I have to exchange the phone ASAP. He made an appointment for me that day and I went in and exchanged it. The Genius looked at the inside of the headphone jack and saw the white burns in there. They were there. I saw them too. He did some tests on the phone and told me that my 3G chip was fried. That is why it wasn't working. He then asked me some questions and I told him about the heat of the Power Slider. He suggested I do not use it anymore and return it to Apple for a full refund.
I went on line and did some research about the Power slider and found out that there have been many people who have complained about the heat and then they have had problems with their phone.
I would think that I had a faulty Power Slider, but that was my third Power Slider and my second phone. I am not going to go for a fourth or fifth Power Slider.
I just wanted to alert anyone out there who has used it and then their phone went buggy, there is a possibility that the Power Slider is the culprit.
I hate this because the Power Slider is a great concept, I just wished it worked.