Can anyone tell me which format is best to present freebies in so that people who use other that P8 can use them, and how ought the folders be organised? Thanks

It really depends on what it is you're contributing as a freebie :)

The standard is placing all of the files within a .zip file, with a Runtime folder being the top.

If it's a texture, it will look something like this.

Runtime

Textures                            Libraries
Your Folder Name                            Pose 
Your Textures                     Your MAT Pose folder
                                      Your MAT Poses
 

If it's a figure, you'll add a geometry folder in the Runtime folder, and a Figures folder in the Libraries folder.

Same for Props, only you'll put it in the Props folder, not the Figures.

Alternately, you can use Materials instead of MAT Poses, but either can work.  

Your best bet is to study some freebies that you like, and see how they are set up.  

 It is props only, Jen, 

I'd say either .3ds or .obj are the most prevalent fprmats that most applications can load or import.. ...

If it's just static props, I would say that OBJ with the MTL file and textures in the same folder would probably reach the widest user base, as that would import into many different programs, Poser included.

Quote -  It is props only, Jen, 

so, Props only, no texture?  You could probably get away with just the .obj and .mtl file in the one zip, with instructions that it's all there is to it, and to import into the program of your choice and add materials to their liking.

I agree that obj format is the most versatile as this is recogonized by 99.9% of all 3d applications as this can be either imported or directly opened (or both) by the chosen application. As a rule it would be advisable to include in the zip any image based textures that are used as well.
3ds is anouther common format but some programs do not handle this format so well and usually you will find that those programs that recognise 3ds also recognise obj.
Just note that obj is also referred to as "wavefront obj" which is exactly the same format.

hope this helps.

When uploading which catagory should I choose to upload as a wavefront obj?

I'd go with Misc., myself.   

 Oh, and don't forget to tell people about it in the freestuff forum!

If its intended for a Poser or Daz studio users then a pp2 file (prop) and thumbnail just zipped with no paths is OK. The prop file will have the embedded geometry and can be unzipped to any prop folder the user wants. 

Put it up at sharecg and you will get tons of downloads .

 Thanks for the info all :)

however, (playing devil's advocate) Uvmapping and texturing will get more people to try it. You have to add a textures folder in your zip file, but it can be done without too much trouble...

 Sure wish more artists were concerned with this... especially those who use Vue. Many, many of those things would be nice to have in Poser, but the artist fails to offer it in a format that other programs can access. I'm sure their sales would be much larger if they did so. 

Quote -  Sure wish more artists were concerned with this... especially those who use Vue. Many, many of those things would be nice to have in Poser, but the artist fails to offer it in a format that other programs can access. I'm sure their sales would be much larger if they did so. 

I agree entirely which is why, when I release anything I ensure I release it in obj/carrara/and bryce which tends to offer a full spectrum. I still have to get my head around how poser 6 works regarding rigging etc and then I will be releaseing in poser formats as well but I find this is a subject which holds very few good tutorials.... unless I am looking in the wrong place (grin!)