They aren't "houses" like morrowind. They are more like counties from Oblivion.
True, but it sounds like the Hold governments will be a lot more important than the county governments were, much like the Morrowind houses.
For the sake of being informative, here's a nice database of what we know about the Holds, including the information from this thread:
THE OLD HOLDSThere are four Old Holds. These are the most conservative, Nordic Holds. They're the most likely center of an anti-Imperial rebellion, are populated mainly by Nords, and are still ruled by kings. The Old Holds are:
Winterhold: Skyrim's long, icy, snow-covered northeast coast. The capital of Winterhold is a major city, also called Winterhold. The city of Winterhold contains the Ysmir Collective, a library supposedly rescued from the destruction of Morrowind, and is influenced by Dunmer culture. It's one of the major trade ports of northern Skyrim. Winterhold also contains the city of Dawnstar, and the ruins of Saarthal, the first human city in Tamriel.
Eastmarch: A volcanic tundra in eastern Skyrim, on the border with Morrowind. The only major city in Eastmarch is Windhelm, the ancient capital of Skyrim that contains the palace of Ysgramor, the possibly mythical culture hero and warrior-king said to have been the first King of Skyrim and the first human in Tamriel. Windhelm is also the location of the Imperial garrison that guards Dunmeth Pass to Morrowind.
The Pale: A snowy valley, south of Winterhold. Contains no major cities that we know of. http://media.pcgamer.com/files/2011/02/The-Elder-Scrolls-V-Skyrim-Dragon.jpg.
Rift: A valley in southeastern Skyrim, home to a forest of birch trees that supposedly resembles "rural New England in fall." The only major city is the city of Riften. We know basically nothing about Riften. http://media.pcgamer.com/files/2011/02/The-Elder-Scrolls-V-Skyrim-Ranger-Hunting.jpg.
THE WESTERN HOLDSThese Holds are more cosmopolitan, and are ruled by elected Moots rather than hereditary kings. They're also the most likely to be loyal to the Empire.
Solitude: Also known as "Haafingar," Solitude is a major city in northwestern Skyrim that appears to be the capital of a Hold we don't know the name of yet. Solitude is the northernmost city in Tamriel, and a major trading rival to Winterhold. The city is home to the Bard's College, a famously liberal institution, and has a tradition of burning effigies of a mysterious "King Olaf," one every year. Their main exports are lumber and fish. Solitude, unlike the other western Holds, seems to have had a monarch as late as the end of the Third Era. The most important ruler of Solitude was Potema Septim, the Wolf Queen. The daughter of Emperor Pelagius II, she overthrew her niece, Kintyra II, in order to put her own son, Uriel III, on the Imperial Throne. She was eventually defeated by her brother Magnus. Potema is a legendary figure and there is an underground movement to restore her bloodline, called the H?rme.
Whiterun: The central tundra of Skyrim is named after its capital, also called Whiterun. The city of Whiterun lies at the base of the Throat of the World. Once known as "the Imperial City of Skyrim," it was devastated toward the end of the Third Era by H?rme and frost troll attacks and a bitter dynastic feud. It is now ruled by a coven of witches, founded by the Witch-Queen Jsashe, who are supposedly priestesses of Lorkhan. At the peak of the Throat of the World is the settlement of High Hrothgar, home of the Greybeards, the world's greatest masters of the art of Thu'um (a.k.a. dragon shouts).
Falkreath Hold: A valley in southwestern Skyrim, home to a boreal forest. Falkreath Hold was actually once considered part of Cyrodiil, and was the land ruled by King Cuhlecain, whose armies were led by Tiber Septim to forge the Third Empire. Falkreath Hold's capital is the city of Falkreath. http://media.pcgamer.com/files/2011/02/The-Elder-Scrolls-V-Skyrim-River.jpg.
The Reach: The most cosmopolitan Hold, in western Skyrim, the Reach is a land of canyons and mesas. The largest city in the Reach is Markarth Side, a city mostly known for being the home of Tiber Septim's Imperial College of the Voice, established to promote the study of thu'um (it didn't work). http://media.pcgamer.com/files/2011/02/The-Elder-Scrolls-V-Skyrim-Tower.jpg.
It also looks like there's another Hold southeast of Solitude, but we don't know anything about it, other than that it's probably a "Tundra Marsh."