Merging data from a program like Excel into Indesign and outputting as a series of PDFs is a fairly simple procedure, and one of the many features we explore in our Adobe Indesign courses. 
Firstly, open Excel and create a simple spreadsheet with 5 columns & 5 rows, like the one illustrated here. Note that the top row must represent the value fields. When all the data has been entered, go to: File > Save As > Other Formats > CSV format.
Next open Indesign and create an A4 letter or flyer. You may wish to place text from a Word document, as usual. All the normal design features and functions apply at this point. Type {} (beside the letter P on your keyboard) as a placeholders  where you want the data to appear.
Then go to: Window > Utilities > Data Merge (CS3 users need to go to: Window > Automation > Data Merge). In the Options field: Select Data Source > then browse to your CSV file > Open > and note the Excel fields in the panel.
With the Type tool, highlight the first placeholder {}. Then click on a field name in the panel (First name, Surname, Company, Location, Event). Repeat for the other fields > you could make them bold or change the colours to see the content change.
The final step is to go to: Data Merge options > Create Merged Document > Records per doc page: Single Record > OK. A new Indesign file will be created with Multiple pages. Save it. Then File > Export to PDF, Epub, etc.
More tips can be found at the Sydney Indesign User Group which meets bi-monthly in the city, and is a free forum for designers to discuss topics and the latest Indesign features. See many examples of our own clients’ work on our Facebook page.
Other related Indesign Blog Posts:

• Indesign images and text
  
• Indesign workflow
• Indesign templates
• Indesign page numbers
• Indesign add hyperlink