FindMyPast.ie has released two more excellent resources: The Post Office Annual Directory 1843 (650 pages) and Calendar 1858 (700 pages). These directories are extremely rare and valuable sources of information for anyone researching their Dublin ancestors.
There are also listings for many of the professionals, including legal and medical, and senior staff at Trinity and the College of Maynooth.
An added bonus comes in detailed descriptions of suburban towns and villages of 19th-century Dublin.
And so to the bad news. It seems the project to digitise the Tithe Applotment Books is seriously delayed. Of course, it was already obvious there had been some kind of hitch because they were originally expected to be released in the spring (April, if my memory serves me correctly), but the announcement suggests it's going to be some time before this early resource will be online.
While the Tithe Applotment Books are held by the National Archives of Ireland, the digitisation process is being carried out by Family Search, the genealogy team of the Church of Latter Day Saints in Utah. Apparently, the indexing project has so far completed only 40% of the documents, so it could be months before this resource is available to all on the Internet. (In the meantime, they are available on microfilm at the NAI in Dublin and at PRONI, and you can find out more about the genealogical value of the Tithe Applotment Books here.)