Tasksel is an installation system that is an integral part of the Debian installer (it is also included in Ubuntu). Tasksel groups software packages by tasks and offers an easy way to install all the packages needed for that task. It provides the same functionality as using conventional meta-packages (ubuntu.com), from description above we have conclution that tasksel is just another way to install an application in ubuntu/debian familly basides aptitude, synaptics and dpkg. The basicaly different betwen tasksel and other application installer is we can iuse tasksel to install more than one application in one moment, using tasksel we can easily build server such us lamp-server, dns-server, mysql-server and also we can upgrade from ubuntu desktop to ubuntu server. tasksel is running in terminal so we can use it in the time we did a connection using ssh/telnet.
Tasksel is not defaultly installed, we must install first before we can enjoy tasksel facility To start using tasksel  we can go to application > accessories > terminal then type 'tasksel',  afterward your terminal will show several package list which can installed by marking using 'spacebar'.

If all package has been marked, move cursor to '' then squeeze the spacebar to start package installation. here  a list of package we can installl using tasksel :
  1. Basic Ubuntu server
  2. Cloud computing: Walrus storage service
  3. Cloud computing: all-in-one cluster
  4. Cloud computing: cluster controller
  5. Cloud computing: node controller
  6. Cloud computing: storage controller
  7. Cloud computing: top-level cloud controller
  8. DNS server
  9. Edubuntu server
  10. LAMP server
  11. Mail server
  12. OpenSSH server
  13. PostgreSQL database
  14. Print server
  15. Samba file server
  16. Tomcat Java server
  17. Ubuntu Enterprise Cloud (instance)
  18. Virtual Machine host
  19. 2D/3D creation and editing suite
  20. Audio creation and editing suite
  21. Edubuntu KDE desktop
  22. Edubuntu desktop
  23. Kubuntu desktop
  24. Kubuntu netbook
  25. LADSPA and DSSI audio plugins
  26. Large selection of font packages
  27. Mythbuntu additional roles
  28. Mythbuntu frontend
  29. Mythbuntu master backend
  30. Mythbuntu slave backend
  31. Ubuntu Netbook
  32. Ubuntu desktop
  33. Video creation and editing suite
  34. Xubuntu desktop
  35. Edubuntu live DVD
  36. Kubuntu Netbook Remix live CD
  37. Kubuntu live CD
  38. Kubuntu live DVD
  39. Ubuntu Netbook live environment
  40. Ubuntu live CD
  41. Ubuntu live DVD
  42. Xubuntu live CD
.. and now we don't need to worry if we want to build a server application such us lamp, dns, or mysql.