I need a model businessplan wich includes all the standard components
like Marketing, Financial plan for a few years, Executive summary,
SWOT analysis, competition analysis etc etc. - It should be no longer
then 35-50 pages (without attatchments) and suitable as a model for my
businessplan. My business is about marketing an new educational
software in the USA.

You need nothing of the sort.

The only real reason for a business plan is to get someone to give you money.
- either as a loan, in which case you will need assets
- or for 'participation', in which case they will grab control

You need about 3 sheets of A4
- the fewer, the better

You describe the market verbally, you provide the odd tempting table or graph.

You describe the minimum and maximum resources you need.

You provide (sensible) sales/nett income projections, preferably worst
case and best case.

You then pin that onto a pile of appendices, ideally they are vaguely
relevant, but mainly they are just to add physical weight to the
dossier.

If you look too slick, people will smell a rat
- something that is interesting and rapidly digestable will get pushed
up to the real lending analysts
- especially if you make yourself look vulnerable to being ripped off

They have some samples here: http://www.bplans.com/sp/businessplans.cfm

Otherwise, there is letny of inexpensive software to help you or you
can goto barnes and noble and thumb through some books on it.