I guess you could it is a very common word I guess. You could check domains in:
http://www.who.is/whois_index/t/domain_list.t.0718.php
if you search in their database it will give you a list of all the taken and available domains with that "guide" word. You can check here to use it in a more unique way as to make your site stand out when people Google with the word guide. I did that and wrote down all available names for translators and then went to the Google keyword tool to see what keywords would be good to add in my domain and came up with spanishtranslationexpert.com which is 3 keywords for my site to see if it will help with my traffic once the site is up and running. (by the way I am not self promoting since I haven´t put up the site yet) After you get the keywords you can go to the Google directory and check the competitions name to get an idea of how to stand out I guess. So here are the links to the sites I mentioned:
https://adwords.google.com/select/KeywordToolExternal
http://directory.google.com/
Well I wish you success and good luck.