As of April 2009, I decided to discontinue the development of ActiveRecord::MultiConditions to concentrate my efforts on other projects.
If you are looking for a good alternative, I encourage you to have a look at Ben Johnson’s SearchLogic library. SearchLogic provides all ActiveRecord::Multiconditions features along with many other cool stuff.
There are many other projects that needs my assistance at the moment. I’m planning to release a new version of Tabs On Rails with multiple tabs support, the Google Analytics on Rails plugin needs to be completed and I’m working on a couple of Rails products. I definitely want to make a private beta version of GetLinkTo available in a couple of months.