Bash is a good shell replacement for the minimal included ash, which does not support aliases.
BusyBox v1.6.1 (2007-09-27 18:08:59 EEST) Built-in shell (ash) Enter 'help' for a list of built-in commands. Nokia-N800-50-2:~# alias cdl="cd $1;ls -al" Nokia-N800-50-2:~# cdl /home/ drwxr-xr-x 3 root root 0 Dec 11 10:41 . drwxr-xr-x 24 root root 0 Dec 31 1969 .. drwxr-x--- 41 user users 0 Jan 18 04:05 user Nokia-N800-50-2:~#