Ok, so basically this is what I need to be able to do:

- Convert AVCHD files from my Sony NEx-5N to cineforms´ format
- Open cineform projects on Premiere CS5
- Use cineforms´ effects to maximize productivity instead of using Premieres´effects (or magic bullets´ to a certain extent)

I´ve downloaded Neoscene and I can convert the files to cineforms´ format but I don´t see any cineform project templates on Premiere nor are there any cineform effects on the video effect list on Premiere. Which version of cineform do I need for this?

In their Pre-GoPro era, NeoHD would be best for what you need as it comes with Premiere timeline presets. It's selling at $249 at videoguys.com. I paid $399 March 2011..

CineForm Studio Premiere has all the features of the old NeoHD and much more for $299.

Is there any other less expensive alternative? Taking in consideration how little video work I do these days paying us$300 is not really a very wise investment. Is there any intermediate solution?

You can stick with NeoScene for $100. There is also Matrox HD codec you can use for free.
Matrox I-Frame Intermedia HD Codec | L.A. Color Blog (http://lacoloronline.com/blog/?10041-Matrox-I-Frame-Intermedia-HD-Codec)

Both NeoScene and Matrox won't get you any editing acceleration

I also put together a tutorial to edit with Matrox codec
How to Edit DSLR Footage in Premiere Pro CS4 | L.A. Color Blog (http://lacoloronline.com/blog/?10118-How-to-Edit-DSLR-Footage-in-Premiere-Pro-CS4)

Thanks, but it´s not clear to me what is the point of the matrox codec if it won´t help me with editing acceleration.

I can tell you now, it won't have any editing acceleration. But you want it cheap.Nothing is cheaper than free =)

I might be wrong, I think you can edit with those AVCHD files from NEX-5N directly with CS5. I have the same camera.

Yes, you can edit the NEXs´avchd files directly on premiere but AVCHD is not the smoothest format to edit.
I got curious about what benefits of the matrox codec though....could you elaborate?

Matrox HD Codec was used to be locked to be used with Matrox hardware codec only. I still have the Matrox RTX2 card so I know the codec are in high quality.

In CS4 it won't edit DSLR .mov files natively. That's why I start converting those h.264 mov files to Matrox AVI. But now in CS5, DSLR MOV is supported natvely.

It's exactly what you said, AVCHD isnt' the smoothest video format to edit. Matrox codec has the I-Frame which is better for editing.

Many thanks for the tips, Taky.