Hi.
I'm in North Yorkshire too. You would be best off getting some decent leaflets printed (see the Vista Print subject on this forum) and go knocking on doors in the areas that you want to work. Don't say that you are starting up a new business - tell 'em that you are expanding your business into their area. I promise you that you'll pick up a load of work in no time. Even without advertising, I usually get offered work off someone every other day when I'm cleaning.
As for pricing, I aim for around £20 an hour so a small semi that takes 20 minutes I price at £7- £7.50. All other prices work off this; so a larger semi with a conservatory would be £12-£14. For a large detached I charge £25 if it takes an hour. Don't be afraid to charge a fair price and don't be talked down EVER!
I have been talked down in the past and those customers are usually the worst. Tell them your price and let them take it or leave it. If you price too cheaply just to get work, you will regret it very soon. Clean less windows for more money.
As for ladders, I use aluminium at the moment. They are reasonably cheap, last well and are light to carry. I have no problems with the cold metal in winter as I wear neoprene gloves on the coldest days.
Wood ladders tend to feel sturdier though on windy days and your hands stay clean (unlike aluminium).