Hi, I always take a look at the Google Cache of a website which (In the case of cloaking) shows what the Search Engine sees. If a website has the NOARCHIVE meta tag therefore prohibiting the a search engine from archiving the content then I do further investigation. I am not saying that all sites that have the NOARCHIVE tag are cloaking and are blackhat but it is one indicator that they may be doing something blackhat and could warrent further investigation.
Also, use FireFoxs fake useragent plugin to look at the website as Google, provided the website is not doing IP Based cloaking then they might give up some extra goodies as well.
Finally, take a look at the website via translate.google.com, many cloaked systems sometimes show the cloaked page to you
Regards
MDS