App Engine releases full-text search
googleappengine.blogspot.com.es
googleappengine.blogspot.com.es
That said, bummed that the compound filtering expressions are apparently not powerful enough to find ranges [2], and therefor filter based on location. Sigh, guess we're still stuck with geoboxes for a while longer.
[1] http://www.billkatz.com/2009/6/Simple-Full-Text-Search-for-A...
[2] http://code.google.com/p/googleappengine/issues/detail?id=72...
https://developers.google.com/appengine/docs/python/search/o...
[1] Technically you can make Solr run by using a AppEngine port of Lucene and a lot of hacking of the Solr code, but it doesn't work well.