hmmm... that was probably me who said that.
basically the problem is that OSAS means lots of different things to different people. It's kind of like when you say that you are christian. As you've probably figured out, the term "christian" can have a very broad range of meanings, everything from conservative catholic to methodist to eastern orthodox to calvinist to quaker and so forth.
Now, to get back to the point... When I denied believing in OSAS, what I meant was I reject the notion that once one makes a profession of faith they are saved forever no matter what they do. The Calvinist position is that God infallibly elects certain people to salvation, but that this is only *fallibly* known in this life. So, if someone makes a profession of faith but they walk away or their works don't evidence their conversion, we would not presume they were saved. In distinction to this, there are people who teach that one can be saved and then fall away or not show evidence of salvation but yet still be saved. In the theological circles I run in this position is called OSAS (whereas the calvinist position is typically referred to as "perseverence of the saints").
To put it another way. for the calvinist, only God knows who is truly elect, and he does not loose these people. However, from man's point of view we can fall away and apostasize.
Personally, I find that most people don't like to be labelled as "OSAS" because it has become somewhat of a derisive term, like "fundamentalist".
anyways, that should help...
ken