If you wanted to use macros in Google Spreadsheets, there's a good news: Google Apps Script is now available for all Google Docs users. That means you can write scripts for performing repetitive actions, creating custom functions or even adding advanced features to Google Spreadsheets.
You can try one of the featured scripts by opening a spreadsheet, clicking on the "Insert" menu and selecting "Script". Unfortunately, Google's sample scripts aren't very useful: you can play Hangman, draw a fractal, convert a named range to a CSV file or translate the text from a cell into 10 other languages.
After installing a script, you need to reload the spreadsheet to be able to use it. Then you have to find the UI element that triggers the script: usually it's a new menu. Clicking on the menu entry doesn't run the script: you first need to authorize the script and then you have to click on the menu entry one more time. It's not user friendly.