A very well written article is now available over on the FontFeed (the blog of FontShop) about the various weights and styles that can come in any type family by Yves Peters. Styles, Weights, Widths; It's All in The (Type) Family focuses on several things, one being the mention of difference between obliqued and italicized type:

While an oblique looks like a slanted version of the roman weight, an italic has a different design. Most notably the double-storey lowercase "a" and "g" turn into single-storey forms, although some designs preserve the double-storey "g".

Don't miss the handy list of typography-related abbreviations on Unzipped, something that can be useful!