I had the exact same symptons with my house. The first thing I did was to call the local electric company(ComED), and they came out and tested the line outside for free. They said there was nothing wrong, and it was something internal.
Do you have fuses or breakers?
Knowing it was internal, the first place I went to check on things was in the fuse box. When I opened it, I noticed that one of the main cable coming into the house was shorting out and marking a visible electricty arc. It would make a snapping noise, I would see the electricity jump from one point to another, and the lights would DIM. What I did to fix this was get a piece of rubber, and shoved it in the space were the short was, and this solved my problems. I dunno if this will solve your issues, but it helped out mine.
If you are unsure of what is save to touch, or unsure was to do, call up a few electricians, tell them your problems, and ask for how much they will charge before they come out to even look at things. Some electricians will charge $150 for just taking a step inside your house, so be careful.
It also sounds like you may have a bad main breaker in your fuse box, if you have breakers.
BE VERY CAREFUL when dealing with electricity in your home. It's not worth your life to save $100 bucks having an electrician fix something for you.