Today I published the notebook Vector and Tensor Algebra and the accompanying package tensalg.m on my homepage
http://www-irm.mathematik.hu-berlin.de/~sulanke/. In difference to the tensors (being Arrays) considered in connection with the built-in Tensor functions in Mathematica I created a tensor object admitting to treat covariant and contravariant tensors as well as tensors of mixed type. Here you can see the contents of the notebook:
http://www-irm.mathematik.hu-berlin.de/~sulanke/Notebooks/vectensalg.pdf. The notebook is written in a style intended to help beginners to work with Mathematica and at the same time to study tensor algebra. For hints and comments to the material, which covered the affin tensor algebra and the exterior algebra over a finite-dimensional vector space, I shall be very thankful.