Digital Use Pricing?

I mainly shoot photography as a hobby and only recently put up my pictures for sale on the web, so I do not have much experience with sales.

I was contacted recently by someone that wants to use a couple of my shots for their webpage. What kind of questions should I ask and how much should I charge?

I will ask how high of a resolution they need and what context will the pictures be used. Should I ask for my name to be by the picture to show who took the picture? Depending on the type of site, should I ask for a link to my gallery?

How do I give them the right to use the pictures on their webpage without giving them the right to reproduce or share them with anyone else?

Thanks for any help you guys can provide.

Last question first, send him a letter and email, explaining EXACTLY what he can and cannot do with it. i.e. web use only, and nothing else.
As for resolution, 1024x? and under 1mb should be fine for web use. A credit is always nice, as is a link to your site, but don't put any value on this. Just remember that a credit and a buck ninety will get you a coffee.
Finally, price. You have tro ask yourself what's the image worth to you? If it's the BEST pic you've EVER taken then charge accordingly.
I was asked to shoot a group shot by a band while shooting a summer ball, recently. They liked it enough to ask for full rights, so I figured "why not?" and let it go for £150. Not the best I've ever taken, but a fair return for 1/60th of a second out of my life.