Moonbug, many years ago when I was a young woman it was easy. 4 ply meant worsted weight, 2 ply was sport weight, etc. That is not the case anymore. Worsted weight can have only 2 strands and so on. Ply simply refers to the number of strands twisted together to form the yarn. Here is a way to use/substitute some of your yarns:

2 strands of Fingering weight yarn = Sport weight yarn
2 strands of Sport weight yarn = Worsted weight yarn
2 strands of Worsted weight yarn = Bulky yarn
3 strands of Worsted weight yarn = Super Bulky yarn

And you may get some help at the link I am posting (look at number 4).

Here is a link that might be useful: yarn help

Thank You Donna, its been quite awhile since I've worked with yarn, as you can tell ! It sure isn't like you said and I know, when this was that and that over there was that! I'm still wondering about a convertion chart, there must be one out there somewhere. What ever happened to ..... easy to understand and work with ? ? ? ? ? With nothing taken away from the different yarns there are today.

Went to the site you wrote down and that is helpful, I'll be going back there more, yet I'm still confusted, I do hope to get it at least kinda put in its place so I can make the dress and hope it fits !

Thanks Again you've been very helpful and also refeshed lots of what I had forgotten.

Hi Moonbug--if you do decide to go look at new yarn (it's snowing like crazy here, too...) what you'll need to pay attention to is the gauge. There will usually be a place on the yarn band that says something like "18 st = 4" (on imported yarns it might be a diagram). A yarn that will give you the same gauge as the pattern should work out pretty well. Is anybody out there old enough to remember when Red Heart worsted was 100% wool? ;-)