Front windshield cleaning, from inside.

If you're referring to the difficulty in reaching the very bottom of it due to the angle, you can buy a triangular cleaning pad on a stick, which works well. You can find them at the local auto parts store, or at Griot's Garage:
http://www.griotsgarage.com/product/window+cleaner+set.do?sortby=ourPicks

 

There's a gadget I found at Bed, Bath & Beyond that's got a rectangular green microfiber cloth over a foam pad on an extentable black plastic handle. It came with a spray water bottle which I discarded. It was a "As Seen On TV" item. There was an extra microfiber cloth in the kit.

 

I first bought the one from BBB but eventually wanted a better quality one once I saw how convenient they were. I then bought the one exactly like the Griotts Garage which is MUCH better. For all my windows I have found the following works flawless. I use white terry towels that I got from Costco as a 100 pack or some rediculas amount. I use a spray bottle with Optimum No Rinse car wash at their detail concentration. This is by far the best window cleaner I have ever used. Use one light spray per window and it is crystal clean and no streaks. I'm a huge fan of the No Rinse product. I haven't tried the latest version which is supposed to be even better because I still have half a gallon of the old formula.