Despite the current fashion of dismissing business plans, where can one find some examples of serious business plans? serious != school assignments. Of course plans from successful companies are preferable, but success can also be related to a tighter corporate hold on plans.
Some starting points:
Viaweb: www.paulgraham.com/vwplan.html
Extracts from Yahoo's 1995 plan: http://www.stanford.edu/class/e145/materials/Yahoo_1995_STVP...
.com era from the Business Plan Archive: www.businessplanarchive.org
And another era: Eckert & Mauchly's Business Plan from 1946 http://archive.computerhistory.org/resources/text/Eckert_Mau...