The Texinfo package contains the info, install-info, makeinfo, texi2dvi and texindex programs
The info program reads Info documents, usually contained in your /usr/doc/info directory. Info documents are like man(ual) pages, but they tend to be more in depth than just explaining the options to a program.
The install-info program updates the info entries. When you run the info program a list with available topics (ie: available info documents) will be presented. The install-info program is used to maintain this list of available topics. If you decice to remove info files manually, you need to delete the topic in the index file as well. This program is used for that. It also works the other way around when you add info documents.
The makeinfo program translates Texinfo source documents into various formats. Available formats are: info files, plain text and HTML.
The texi2dvi program prints Texinfo documents
The texindex program is used to sort Texinfo index files.