A friend who is buying a business is needing a number of spreadsheets, contracts and legal forms. That got me looking for reputable and reasonable places to find sample business forms online today.
For US-based businesses, I found these three:
Lots of checklists useful for going into business, a nondisclosure agreement and a large selection of employee/HR related forms. Financial templates are useful, but ignore the US tax forms. Go straight to the IRS forms section to get the current ones.
A good selection of sample forms, spreadsheets and contracts covering many different industries and needs. The documents here are provided by DocStoc so the full versions are offered for sale. However, plain text previews are available and may help answer basic questions.
The Tools and Templates includes lots of business-plan related forms and articles mixed together. You can sort them by business stage (startup, growing, exiting). They also have a section En Español, however it seems to be all 60 second guides, without the forms and other goodies.