Check out Applescript and its little cousin Automator.
Yes, AppleScript is what we "scripting" people first reach for. The Microsoft applications have very large AppleScript dictionaries. They are a bit cryptic, and sometimes seem like an unholy merging of AppleScript "natural language" and "VBA syntax". AppleScript can use those dictionaries to do such things as run an Excel XLM Macro. With the just released Office restoring VBA functionality, its AppleScript dictionary is likely expanded also (don't really know about commands to run VBA, but maybe).
AppleScript can also run shell commands, much the same as Terminal, via a command: do shell script
And FileMaker can run AppleScript directly, using the Perform AppleScript script step.
There is also a new language, derived from AppleScript, new as of Mac OS 10.6, which allows you to use many common AppleScript commands within other programing languages; "AppleScriptObjC"
AppleScript forums: http://www.macscripter.net/