I run Aros on my Acer Aspire laptop and an unbranded netbook. I can tell you that Intel GMA graphics are supported, but only through an external monitor at the moment! But never fear, the 24bit VESA driver is fine and it's still super fast.
Audio and ethernet both work on my Acer Aspire, so I can go online and browse the web with OWB (hopefully this gets a new name soon). USB works on both, so I can play games and fire rockets with a control pad.
You can easily try the Icaros and Broadway boot CDs and see if they will run on your system before installing them. Unfortunately I don't know anything about resizing partitions and dual booting with Windows, I wiped that virus-ridden crap off my laptop the day I got it and installed Aros and Linux, using Aros to make its own partitions then using Linux to add its own in the rest of the space. I wouldn't risk partitioning the hard drive from Aros unless you don't mind losing everything on the drive if I were you. It's possible to install it on a removable USB drive though, so you may want to try that after confirming it works from the CD/DVD.
To install Aros, you boot it up from the CD and click on the Install Aros icon in the Tools drawer. This will bring up a GUI where you can determine the size of your partitions and choose where to install the software and boot menu. It's pretty simple really, once you manage to run it from the CD you can be pretty sure it'll run from your HDD too.
Just remember it's still in development, so be ready for a bumpy ride.