I remember when I first started with poser, I downloaded tons and tons of free stuff, more than I could ever use, then when I did need something out of all that, I couldn't find it, I realized I hadn't organize my downloads, and I couldn't tell what things were or how they looked like just by the names, which sometimes weren't descriptive at all.

So my advice is start organizing right away, put all V4 stuff in one folder, inside that folder, create other categories like clothing, textures, props, etc.

And most importanly (for me anyway), save the preview picture of the items you download along with the zip file with the same name like:

someFreebie.zip
someFreebie.jpg

So that you can easily browse your stuff just by looking at the pics.