Based on the same technology as the SharePoint 2007 Search, you too can have Microsoft Search for FREE! As part of the newly released Microsoft Search Server 2008 product line, you can have Microsoft Search Server 2008 Express for FREE!
I would like to point out the differences in the following hierarchy of products from "low-end" to "high-end".
1. Microsoft Search Server 2008 Express (MSS Express). Free (enough said!), but also has support for Search Center, No Pre-Set Document Limits, Extensible Search Experience, Relevance Tuning, Continuous Propagation Indexing, Federated Search Connectors, Indexing Connectors, Security-Trimmed Results, Unified Administration Dashboard, Query and Results Reporting, Streamlined Installation.
2. Microsoft Search Server 2008 (MSS). This product supports all of the functionality listed in the Express edition, but adds High Availability and Load Balancing capabilities.
3. Microsoft Office SharePoint Server 2007. In addition to everything that both of the above versions support, SharePoint 2007 of course adds the great SharePoint Productivity Infrastructure, as well as the People and Expertise Search and the Business Data Catalog (BDC).
Get more details, including the download, at http://www.microsoft.com/enterprisesearch/serverproducts/searchserverexpress/default.aspx