Some of these items kinda belong on more of a wishlist than a todo list.  ;)

> make sure program consistently returns a non-zero return code on
  error, so scripts can rely on it
- add a [sibling] option to .PKGINFO -- used when only one of
  the siblings can be installed at a time (eg, bsdinit,sysvinit)
> handle wildcards on the command line
- sort packages by package name in pacman.db
? manage conditional file installs (ie, 'info' pages)
- maybe add a 'confirm every action' option for doing paranoid installs
- add a consistency check operation
- change char[xxx] to char[PATH_MAX]
- add file locking to db
- add a --dbpath option
+ dependency checking
+ fetch files via ftp
  - need to manage foreign package lists like apt
- upgrade currently does a double db backup; not really desirable