First about the HOA, most agents do put in the HOA and the fees associated with their listings into the multiple listing service (mls), but when other web sites pull information they don't pull all of the fields that are in the mls. So depending upon where you are getting your info you may or may not see the HOA and or fees associated. Second, as for Realty Trac, as stated below, they are a lead generation service for REALTORs to subscribe to. Their information is not real-time in often times is very outdated. As Paul stated, your best bet to find the most recent homes on sale and all pertinent information is to have a Buyer's Agent help you. It will not cost you anything as their fees are most commonly paid for from the seller's proceeds.
Hope this information was helpful!