I as a amateur web designer have had the domain bigger-fish.co.uk for some four years. I have recently been approached by a big design company to say that I have infringed their trademark. What I have read on the web I possibly have, although not intentionally. Not a big loss to loose the domain as I make no money from it. What I would like to find out is it possible to check any other registers to make sure you are not upsetting anybody on trademarks etc when you purchase a domain name.
www.uspto.gov is the US trademark database. I dont know for the UK. Nor do I know .uk's policy on trademark disputes. ICANN uses UDRP which is arbitrated byWIPO mainly. Search 'UDRP' in google and you can find plenty of info on that. But I am not sure that is what you are looking for.
I think it is not really possible to completely protect yourself, you would have to do searches worldwide and then try and figure out if there could be problems with unregistered trademarks. uspto.gov as posted above is the best place to start,