Daniel Morrisette has uploaded mapserver-4.6.0-beta2.tar.gz. Changes since the first beta:
add a small buffer around the cliping rectangle to avoid lines around the edges (bug 179).
Finished code to convert back and forth between GEOS geometries. Buffer and convex hull operations are exposed in mapscript.
fontset.fonts hash now exposed in mapscript (bug 1345).
Retreive distance value for DWithin filter request done with line and polygon shapes (bug 1336).
Don't render raster layers as classified if none of the classes has an expression set (bugs 985, 1015).
Fixed several issues in writing of inline SYMBOLS when saving mapfile (missing quotes around CHARACTER and other string members of SYMBOL object, check for NULLs, and write correct identifiers for POSITION, LINECAP and LINEJOIN) (bug 1344).