Matrix maths and re-parenting objects
Rm * Am = Bm * Inv(Am) * Am
Rm * Am = Bm
Bm = Rm * Am
Note, this works in both world space and local space as long as A and B are both in world or local space. If Am and Bm are in the same local space then once you have Bm you can use the world space transform of A to find the world space transform of B. If Am and Bm are both in world space then transform them to local space by multiplying by the inverse of there world space transforms first.
Links
Collision Detection
http://www.harveycartel.org/metanet/tutorials/tutorialA.html
IIntersection Tests
http://mathworld.wolfram.com/Line-LineIntersection.html
Geometry
http://local.wasp.uwa.edu.au/~pbourke/geometry/
Misc
http://www.gamedev.net/reference/
Vector Maths For Animation
http://faculty.cs.tamu.edu/schaefer/teaching/441_Fall2008/lectures/3DTransformations.ppt
Everything you wanted to know about matrices, vectors, quaternions but were afraid to ask
http://web.archive.org/web/20041029003853/http:/www.j3d.org/matrix_faq/matrfaq_latest.html
Gauss-Seidel
http://www.ee.oulu.fi/~mpa/matreng/eem5_4-1.htm
Steering Behaviours
http://www.red3d.com/cwr/steer/
Character/Animation
http://paulneale.com/index.htm
Mass/Spring/Damper - numerical integration
http://engineeronadisk.com/book_modeling/numericala4.html
http://www.cas.mcmaster.ca/~qiao/publications/MQ08.pdf
http://engineeronadisk.com/V2/book_modelling/engineeronadisk-37.html
Excellent paper on computational methods for producing animated characters
http://www.cs.ucla.edu/~vector/files/BFA_Dissertation.pdf