1970's and '80s originators of the NeoConservative movement like Irving Kristol, Daniel K. Bell, Midge Decter, Norman Podhoretz, and Nathan Glazer used to sort of define a Neo Conservative as 'a Liberal who's been mugged by reality'( a play on the old saying that a conservative is a liberal who's experienced a mugging.)
A lot of the movement's 'leadership' were bright, academic, former Trotskyists from City College in New York. They'd often been leading scholarly advocates for the Left in the 50's and 60's who had the intellectual honesty to re-assess their position when the empirical results of liberal programs('Beyond the Melting Pot' -Glazer and Moynihan) started to pile up ('Losing Ground'-Charles Murray).
'Commentary' was/is their primary advocacy journal(now along with the Weekly Standard), and they've tended to retain their emphasis on the importance of Israel in U.S. foreign policy, and their Left/pre-conservative adherence to 'Wilsonian'foreign interventionism. They vary on fiscal policy, but generally tend to not mind deficit spending as much as Conservatives ('Paleo-Conservatives'?) do. They usually favor a 'free trade/globalism' foreign trade policy associated with the WTO, NAFTA, FTAA, etc. On these points they differ from traditional Conservatism.
Check out 'Arguing the World', a fun profile documentary of the neoconservatives, available at any good video store.