ive posted a short instruction few times already:
http://www.amiga.org/forums/showthread.php?t=57421post #13
download the current nightly. in the distfiles folder you will find an adf archive of a boot floppy. using f.i diskimage device (http://aminet.net/disk/misc/diskimage.m68k-aos.zip)
you will be able to decompress it to a real floppy. also the best is to prepare aros boot partition on a hard disk (just coppy the content of nightly to it and mark the partition as bootable).
now, boot from the prepared floppy drive, which will extract the aros kickstart to ram and boot from there. you can recognize aros kickstart booting by dirty-ocker-yellow color on screen (lol). if you have a bootable aros harddisk partition attached to the system (preferably via internal ide or accelerator scsi) chances are that your system will boot to wanderer. be sure to have it a highest priority hd.
i have tested and can confirm a4k 030/040/060 as working, except for csppc. also many configs of a1200 work, in particular blizzard 1260. there is problem wit elbox fastata so far i see.
note that things get broken now and then, f.i. the build is currently broken and doesnt start on real hardware because further early startup and shell adjustments take place.
edit: just have read a post from toni that this has been fixed now. todays nightly should work again.