buy it for $70usd at controlledvocabulary.com. very highly recommended, will save you many hours of typing synonyms etc. there's also a version for lightroom now - you get 1 yr of free updates and can download as many different formats as you want (for iView, lightroom etc). the author, david riecks is a very nice guy and always posts on DAM forums - v.helpful.
i normally double-click once in the keyword field (yes it's annoying, why can't it be just a single-click? argh) then type multiple keywords separated by commas. I also use the Controlled Vocabulary Keyword Catalog (CVKC) for a huge pre-built list of synonyms etc.
I'm using iView 3.12 though i understand it's virtually identical to EM.
Hey wprasek where do you get the (CVKC) at?