I own danwelsh.co.uk through 123-reg and have the nameservers pointing to JustHost. This allows me to type danwelsh.co.uk into the address bar and it takes me to my JustHost site but has the rather ugly "http://22.214.171.124/~danwelsh/" appearing in the address bar when you get there. Within my JustHost account, if I change the site address and wordpress address to http://danwelsh.co.uk I get a redirect loop when trying to access the content.
I've just added a second domain name (tenminutelectures.com) to my control panel at JustHost which I bought from JustHost and get the same problem. Anyone got any ideas for a fix? :)