These mantras are stored in acrobat, postcript formats and in some cases recordings chantings of the mantras are also made available. The texts were generated with TeX using the devnag package.
Since the fonts used for devanagari are generally not available as X or Windoze fonts neither the Acrobat or postscript versions look great on screen, but should (I hope) look OK if you print them using a 300+ dpi printer. The pdf files are generated with a resolution of 1200 dpi which should be adequate for most situations.
Note that the devanagari text is anotated with melodic structure. No anotation means normal pitch (e.g. e), an accent above a phoneme means pich of phoneme is up one half note (e.g. to f), a line under the phoneme means pich lowered by one whole note (e.g. to d). A double accent means pich goes up one half note (e.g. to f) after half the duration of the phoneme while a double underline means pich is lowered by 2 and a half note (e.g. to b) (this is rare).
The rythmic structure is given by the devanagari text itself through its alteration of long and short wowels.
Even so, it may be difficult to learn these mantras without at least a recording. Even better, of course, would be the guidence of a qualified teacher.