Instead of inserting (or even burning) multiple CDs to install software in debian you can just use the downloaded ISOs.
This method assumes you are going to keep the ISOs and folders available, the ISOs will be mounted at boot time automatically and you will be able to install software from them at any time.
Be sure to replace any instance of my-user-name with your username.
First create a folder in /home/my-user-name/ called isos
Now store all your downloaded isos in /home/my-user-name/isos/ and the isos are named debian1.iso debian2.iso debian3.iso
I create three folders in my /home/my-user-name/isos/ directory called iso1, iso2, and iso3.
I use my favorite text editor with root privileges to open /etc/fstab and add the following entries to the bottom of the file:
/home/my-user-name/isos/debian1.iso /home/my-user-name/isos/iso1/ udf,iso9660 user,loop 0 0
/home/my-user-name/isos/debian2.iso /home/my-user-name/isos/iso2/ udf,iso9660 user,loop 0 0
/home/my-user-name/isos/debian3.iso /home/my-user-name/isos/iso3/ udf,iso9660 user,loop 0 0
Then add the following repositories to synaptic
file:/home/my-user-name/isos/iso1 lenny main
file:/home/my-user-name/isos/iso2 lenny main
file:/home/my-user-name/isos/iso3 lenny main
(The first part is the URI, the second is the Distribution(lenny), the third is the Section(main))
Reboot and then after that the ISOs should be mounted and available in synaptic. Be sure to click reload in synaptic.Tip From here