Visible Euclidean Algorithm - Enter two positive integers, and click the button to see the operations of the Euclidean Algorithm. - http://www.math.umn.edu/~garrett/crypto/a01/Euclid.html
LLL Page - Maintained by Keith Matthews. Papers, examples, pseudocode. - http://www.numbertheory.org/lll.html
Future Directions in Algorithmic Number Theory - Some of the conjectures and open problems motivated by the "PRIMES is in P" papers, compiled at the AIM. - http://aimath.org/WWN/primesinp/
Some Number Records - Connected with divisibility and factoring. - http://www.loria.fr/~zimmerma/records/
Computational Projects in Number Theory - Interesting problems, usually requiring extensive verifications or enumerations, to occupy the idle CPU time of workstations and personal computers. Compiled by Tomás Oliveira e Silva. - http://www.ieeta.pt/~tos/hobbies.html
The LLL Algorithm - Papers on the LLL algorithm and its applications collected by François Koeune. - http://www.dice.ucl.ac.be/~fkoeune/LLL.html
Implementations of Extended LLL - Links and notes by Wilberd van der Kallen. - http://www.math.uu.nl/people/vdkallen/lllimplementations.html
Computational Number Theory - Lecture notes by Robert Campbell, December 1997. - http://www.math.umbc.edu/~campbell/NumbThy/Class/
Basics of Computational Number Theory - Notes and Javascript illustrations by Robert Campbell. - http://www.math.umbc.edu/~campbell/NumbThy/Class/BasicNumbThy.html