Here is a quick AppleScript droplet to bulk convert text files (plain text, rich text, html, some code files like C and javascript files...) to PDF format.
Copy the following script into the AppleScript Editor (/Applications/Utilities/AppleScript Editor) and save it as an application.
Then drag-and-drop files onto it to convert them to PDFs.
on open theFiles
set oldTID to AppleScript's text item delimiters
repeat with thisFile in theFiles
-- get file path as posix path
set inputFilePath to POSIX path of thisFile
-- create output path - same name with .pdf extension
set AppleScript's text item delimiters to "."
set outputFilePathBits to text items of inputFilePath
set last text item of outputFilePathBits to "pdf"
set outputFilePath to outputFilePathBits as text
-- create convert command and send to shell
set AppleScript's text item delimiters to " "
set cmdList to {"/System/Library/Printers/Libraries/convert", "-f", quoted form of inputFilePath, "-o", quoted form of outputFilePath}
do shell script (cmdList as text)
end repeat
set AppleScript's text item delimiters to oldTID
end open
Mac OS X Hints
http://hints.macworld.com/article.php?story=20110605113316760