Lots of places:
1
) mscdex' HPC Software Repository
(http://hpc.communitypage.net/
)
2
) Windows Mobile Today
(http://www.pocketpccity.com/software-hpc.html
)
3
) Tucows
(http://www.tucows.com/search?search_terms=Handheld+PC+Pro&search_scope=pda&search_adv=0&search_size=&search_size_multi=b
)
4
) PDATopSoft
(http://www.pdatopsoft.com/software/pdalist.php
)
5
) PDAGold
(http://www.pdagold.com/software/list.asp?p=3
)
. . . and lots of other places. A Google search will turn up even more.