I've heard that Ubuntu is very easy to use.. to be truthful, i've heard it called linux for idiots quite a few times. Ease of use is pretty subjective though and there's a high possibility you'll try a few distros before you find the one you like best.
Pretty much any distro is going to be able to dual boot. Linux requires a bootloader, which can be configured with options to boot from many different partitions including all the flavours of windows. GRUB and LILO are the main 2. Certain distros may use one or the other by default but you can almost always choose which you want to use.
As for installing on a laptop, check
www.linux-laptop.net. If your laptop isn't listed there, it doesn't mean it's not going to work, but you're probably going to have to spend a fair amount of time tweaking settings and adding support for ACPI, wireless networking, touchpad, etc.
I've never installed linux on a laptop so i'm sure other people can give you other resources. That's just one i stumbled across a while ago.
This is probably going to require some head-scratching and trial and error, so Good Luck!
