Hi Taz,
While compiling the kernel , make sure your primary eth0's driver is built into the kernel, and any secondary eth1 [ie. if u have one ] as module.
Make sure that Alsa is built into the kernel, and the soundcard driver as a modules , and NTFS read write suppoet is enabled int he kernel.
Just follow the Gentoo installation guide [
http://www.gentoo.org/doc/en/handboo...intable&full=1]
1)Section 8.b answers You question about network setup.
2)Section10 give's you details about setting up a bootloader with Xp
3)Yes , you can mount windows drives .