MathNet/MPRESS - The Mathematics Preprint Search System.

One-Shot Preprint Search - Combined search page for many archives. (ICTP, Trieste, Italy)

MathSearch - Search a collection of research-level mathematical and statistical Web material.

Hypatia - Mirroring agent for 1000+ math/cs ftp sites with hundreds of thousands of miscellaneous files.

Bibliographies on Mathematics - Bibliographies on Mathematics, part of the Collection of Computer Science Bibliographies. Searchable.

Hypertext Bibliography Project - Covers a large number of journals in theoretical computer science and related areas.

Project Euclid - Aims to help independent journals of mathematics and statistics by setting up an infrastructure that will empower the participating journals to publish on the Web and to increase their visibility through a combined online presence. Demonstration site.

Mathematics Metasearch Machine - Gives one-pass search of many math sites with concentration on numerical analysis.

EULER: EUropean Libraries and Electronic Resources - search for mathematical resources across Europe, such as books, pre-prints, web-pages, abstracts, proceedings, serials, technical reports and theses. Alpha version.

FermiVista! - Searchable index to articles and preprints in mathematics, theoretical physics and computer science, maintained by Stéfane Fermigier.

Martin's Online Paper Search - A distributed virtual library of papers which are available close to web pages of people from Complexity Theory, Combinatorics and related subjects.

Search sci.math.research - Searchable archive of this newsgroup.