I try to keep this site timely, but it can take a few hours or days for me to report new deaths. But doing research for DPS really isn't brain surgery - most of the answers to the questions I'm asked can be found by doing a simple online search.
First, I rely on the Internet Movie Database for a quick sanity check. Their data is about 98% correct with regards to births and deaths. It generally takes them a few days to get a new death listed, so it's not a great site for the latest information. But it's excellent for legacy information about movie, TV and most stage performers, writers and directors. The Internet Broadway Database is an excellent source for Broadway performer information.
Wikipedia Recent Deaths is reliable about 95% of the time, but fake death reports are still planted there periodically. So don't take reports there at face value - always verify.
To double-check a death rumor, do a Google News search. Generally, if you read about a celeb's death and a death report doesn't show up on Google News in a few hours, it's a hoax.
Needless to add (but, what the hell, I will anyway), Dead People Server has reliable information about the deaths of interesting celebrities. I can't stay up-to-date with everyone - check Wikipedia Recent Deaths for the daily long list. But, if you're interested in the deaths of TV/movie/inventors/cultural icons, link to Dead People Server or the Latest DPS Updates newsfeed. For interesting celebrity deaths from the last 60 years or so, link to the Weekly Blasts from the Past newsfeed.