Google has made an aggressive pitch for its rivals' business customers with a new switch programme for enterprise search.

The new trade-in service pushes its Search Appliance, and offers companies that replace their existing search facilities with Google's version a free Google Mini - the small business version of its search engine. The offer stands until the end of the year.

The Google Search Appliance, first introduced in 2002, indexes information stored in a variety of server-based data repositories, such as intranets, public websites, relational databases, enterprise business applications, content management software and legacy systems.

The Google Mini is designed for small and medium-size businesses that want to make the information in their intranets or websites searchable. Both products are hardware boxes loaded with Google search software.

Google hopes the replacement program will appeal in particular to customers of rival Verity, which last week announced it will be sold to Autonomy for $500 million.

In its statement, Google referred to "the recent turmoil with providers of legacy search solutions" as a good reason for companies to consider swapping their current search systems.

The Google Search Appliance starts at $30,000 to search up to 500,000 documents, while the Google Mini costs $2,995 and searches up to 100,000 documents.