Oligonucleotide design MAD_DPD (download) (Article) This software allows design of a minimal number of degenerate oligonucleotides to cover a somewhat conserved region in highly diverse set of molecules. It uses a simulated annealing type strategy
Batch Primer3 is a server that will pick multiplex primers from a given
sequence
Sequence alignment
PRANK The only application I know that positions gaps with some phylogenetic sense behind the positioning. (available from Nick Goldman's site at ebi.ac.uk)