Try the following to uncompress files:

tar xvzf file-1.0.tar.gz - to uncompress a gzip tar file (.tgz or .tar.gz)
tar xvjf file-1.0.tar.bz2 - to uncompress a bzip2 tar file (.tbz or .tar.bz2)
tar xvf file-1.0.tar - to uncompressed tar file (.tar)

where file-1.0 is your file and:

x = eXtract, this indicates an extraction (c = create, to compress)
v = verbose, (optional) the files with relative locations will be displayed
z = gzipped; j = bzip2-zipped
f = from/to file ... (what is next after the f is the archive file)

The files will be extracted in the current folder (most of the times in a folder with the name 'file-1.0').