Hi,
My name is Miodrag and I am coordinator of MAME project (www.mamedev.org), we would like to distribute seabios roms if possible together with our binaries to show PC capable emulation. All is free and project is under GPL2+ license.
seabios is GPL, so this is perfectly fine as long as you also provide the source code used to build the binaries (as required by GPL).
If you are using seabios unmodified I'd recommend to place a upstream git mirror next to the mame repos @ github. qemu does the same on http://git.qemu.org/, for GPL compliance reasons, and also because it's more convenient that way for the seabios submodule we have in qemu.
If you have patched seabios you have to publish the changes too of course, and I recommend to sent the patches for review and upstream merge to the seabios mailing list (which I've added to Cc).
thanks, Gerd