On my PC I store important files, needed for my work. On Windows I used Steganos safe. It creates encoded virtual drive, which can be seen after entering password. Is there similar (or better ) Soft for Ubuntu? Can I lock folders so that only I could access them?

Look into truecrypt which will create encrypted partitions or encrypted files into which you can make a partition and mount as though it was a normal volume. Uses passwords or passwords and keyfiles to encrypt the files. There's a large choice of encryption algorithms. I have some fairly large files within the encrypted partitions which I can mount under Linux or Windows - which is very handy indeed.

If you just want to hide the contents of a directory from other uses, just remove group and other read/write/execute permissions from that directory with chmod (command line) or nautilus (GUI). This isn't especially effective though, as it's easy to bypass, with a LiveCD, for example.

Just so that you don't abandon the issue, I can assure you such thing exists, and there is even choice.
I won't be able to help you with this however because I was never interested in such a thing for my PCs. Unlike in Windows, not anyone can login, only those allowed to, and then they only can access files that I allow them to.

Yves.

(pwc101 answer wasn't there when I wrote my first post)

If you're paranoid about your data, you may be interested in "PhoneBook", from the FUSE filesystem.

Yves.