I have a 4gb USB thumb drive with Ubantu 9 on it and it looks like I have over 3gb free but I only have 4mb free in the documents Directory. How do I increase the size of the directory so I can add my Doc files?

you don't change the size of a directory, it's just as big as whatever is in it. It would be the underlying filesystem that has a fixed size. What partition layour and filesystem are you using? Generally you'd use a tool like parted to resize a partition and the resize2fs to resize the filesystem within the partition but as this is on a USB stick it would most likely be trickier. can you post the partition layout details of the stick and other useful information?

What are you look at that tells you that you only have 4mb free in Documents?

Do you have quotas set up for users?

When you(?) created the ubuntu installation to the bootable thumb drive, you(?) were asked how much spare space you would like to allocate to "Documents & settings" ( = and other software you might like to install). Perhaps the figure originally chosen was, in retrospect, too small.

This space is generally called "persistent storage" for bootable USB sticks. They used not to have the ability to save anything at all between re-boots, so this is an improvement.

If you set this figure too low when the stick was created, you will not have much space to play with (Eg only 4MB, when you could have made it larger, within the limits of the FAT32 filesystem the stick uses).

I am not sure how you can increase this space (without starting afresh), but I hope I have given you some useful search terms.