I had installed an ubuntu 10.04 to a pen drive of mine. Now, I want to move it to a pen drive with bigger storage. But, how/what software should I use to do that?
Is is possible to upgrade from 10.04 to 11.04 or 11.10, without any problem? I heard only LTS supports upgrade among themselves, otherwise its not possible. Is it true?
I would backup and restore your USB disk image using instructions as described in this link.
Then I would adjust the persistent storage size using instructions such as described here.
To upgrade, you must upgrade in order i.e. 10.04 to 10.10 to 11.04 etc. Canonical only supports this route between LTS versions.
You will be able to move from one LTS version to another in one go since this will be a supported route i.e. 10.04 to 12.04.
Attempting to circumvent these recommendations is definitely not recommended - you could end up with broken packages, files not upgraded or incorrectly modified resulting in a system which would behave erratically, or even just not boot.