If you run mkhomepg at shell, it will refresh your page permissions, and also list a flag you can call the command with again to change the domain that your account's HTML content will be served from. It looks like this:

> mkhomepg
Please place your webpage files in /sdf/arpa/ns/p/username/html.
To set proper file permissions, run 'mkhomepg -p'
To set and activate your custom URL, run 'mkhomepg -a'

If you run mkhomepg -a and are ARPA membership or above, you will be prompted further:

mkhomepg -a
Your URL is currently http://username.freeshell.org
Your webpage description reads:
Description


Do you want to change it? (y/n)

If you choose 'y' to the above prompt, you will see a list that looks something like the following:

36bit.com         A celebration of 36bit computing.
3b1.org           The AT&T 3b1 UNIX PC .. circa 1986
andropov.org      En Russiah, Whe haf ah nyew freedem lyke en vest haf.
beevomit.org      Its *honey* .. didn't you know?
buckybits.com     Those bits that get frobbed when you hyper-control-function
bughlt.org        BUGHLT - error condition on the PDP-10
chaosnet.org      A networking protocol for LISPMs, ITS and others
decsystem.org     Designation used for the PDP-10 KA/KI/KL/KS machines
deskshots.org     Hot and steamy 640x480 images of other people's desktops
feckov.org        In loving memory of Father Jack Hackett
freak.net         Shut up You Freak! Its a madhouse! A MADHOUSE!!!!
freeshell.net     Free Shell Network
gekiganger.org    OK! Ken! Joe! Akira! .. LETS, GEKIGA IN!
godsong.org       Either something very beautiful or terribly frightening!
gomen.org         Japanese for 'forgive'
gopherite.org     Either a mineral salt or a respected citizen of GOPHERSPACE
hactrn.org        HACTRN - A real hacker's tool
inlisp.org        When all else fails, WRITE IT IN LISP!
jerq.org          The internal code name for the AT&T 5620 Dot Mapped Display.
loompaland.org    Help Mr. Wonka rescue the poor oompa loompa!
maclab.org        MIT Project MAC - See the JARGON file
maclisp.org       MIT Project MAC LISP for the PDP6, Multics, TOPS-20, et cetera
macsyma.org       36bit mathematics at its finest
maikosoft.com     A Kyoto based software company owned and operated by Maiko-san
massbus.org       The proprietary BUS interface of the PDP-10
metapath.org      Transcend the MUNDANE on the MetaPATH
motherarse.com    Ask a Japanese person to say 'Mother Earth'
multics.org       UNIX came from MULTiplexed Information and Computing Service
myjp.net          My Japan .. no, not yours .. MINE .. gomen ne!
natverk.org       NETWORK i svensk! Also used for the SDF UUCP network
netlsd.com        Timothy Leary's personal distribution network
ntfn.org          North Texas FreeNET never was due to a 200K+ annual budget
paunix.org        Public Access UNIX
pdp6.org          The digital PDP6 computer .. play spacewar? 

At the end of the list, you will be asked to type in the new URL base for your web space and to confirm it, and that will be it!