Floorplan and site plan software recommendations?

Part of obtaining permission to put up my new shed along with other projects on my property requires me to Lodge a development proposal. With that proposal I need to include a fairly detailed site layout plan, current and proposed floor plans along with elevation drawings.

I've begun doing these by hand, and while I've been told it's acceptable to do so, I feel computer generated drawings will look better. It will give things a more professional look, it'll allow me to make changes quickly and cleanly and allow me to reproduce them in whatever quantity may be required.

So what I'm wondering is could anyone recommend any apps, freeware or shareware programs that would be suited to producing those kind of drawings?

Edit: these are preliminary drawings, and while they should be to scale and will need to include dimensions, they won't need to be full blown architectural plans and renderings. 

Sketchup is free.

Yeah, SketchUp isn't exactly suited to what you're doing, but it's free, easy, and you can dimension with it.  The hard part will be outputting it to scale.  But as long as it is well dimensioned that shouldn't really matter as long as it's close.

3d home architect. 

I'm sure by now you can find it for free, but I don't have any way to upload a copy for you at the moment. 

My county office took everything I had, then opened a satellite view map of my property, marked the rough dimensions on it with paint, and printed it out to go on top of the package.  I would call that the acceptable level of effort to put into it.

Residential, right?

The only thing the building department is looking for on a site plan is the setbacks.  Print a copy of the plat from the tax assessor's website, draw the footprint of the structure on it, and write real clearly what the setbacks from the property lines are (+-)

Preliminary building plans should be fine with a basic sketch.  Show the dimensions of the building, and the overall height (if you can).  Don't do the architect's job for him.  

You are in Australia.  I have no idea if you will need architectural or engineering drawings or not.

SweetHome 3D is a free product that looks like it should work.

Thanks for the suggestions, I'll have a play with Sketch up and look into the others suggested. If nothing else it'll be interesting to translate mental pictures and rough sketches into a more tangible 3d product that my partner will better understand as she can have a real hard time visualising something that's not there.

In reply to oldopelguy (Forum Supporter) :

That's actually a pretty interesting idea, and it's good to hear first hand how straight forward these things can be. Probably shows I'm overthinking a bit

In reply to SVreX (Forum Supporter) :

Yes, Residential.

I hear what you're saying, and I agree, setbacks and heights are probably the key info they're looking for at this stage. It's a proposal and they're not issuing a building certificate based on that alone. True to form, I've over thought it... 

Depending on council's requirements, I may be the architect. I'm going to try and set up a meeting with them when I lodge my development application so we can discuss exactly what requirements they have for the various stages of the project. I'll be registered as an owner builder with them for this project, so I guess I should be able to get a far clearer understanding of what they expect after sitting down and discussing it with them.

Thanks for chiming in, your perspective when it comes to construction is always helpful and valuable insight.

Note:

Dont put exact measurements of the setbacks on the plat. Know the requirements, and exceed them generously, but don't be specific. 
 

For example, if the setback requirement is 5', and you have a little room to spare, write "10' (+-)". If it turns out being 8', oh well. 
 

If you write 10' and it ends up being 9', 10 1/2", they'll be fighting with you for 1 1/2" (even though you exceed the minimum reguirement of 5')

If you are dealing with specifics, you will be needing a surveyor, etc. 

In reply to SVreX (Forum Supporter) :

Thank you, I'll bear that in mind. I'll try to use round numbers and (+/-) unless pressed further. Having wiggle room is important because things don't always go exactly as planned.

Thankfully, being a semi rural area, the council seems to be fairly understanding and willing to work with people. For example, they're willing to issue a variance for my shed as it will marginally exceed their 100m2 regulation for my block size and zoning.