not quite sure what you are trying to do. also [code] tags make it easier to read.
^i think you are missing backticks
ip=`sudo tail /var/log/syslog | grep "dhcpd: DHCPACK" | cut -d " " -f 9`
now if you want to run a program then add this line to your shell script:
appname 192.168.0.29 &
sends it to the background the script will go to the next line without waiting for it to finish.
this seems more programming appropriate.