Typing Tamil
One of the new features in Tiger and Leopard is the ability to write Tamil using the InaiMathi font and the Anjal and Tamil99 Input Methods. Anjal will unfortunately not display on Keyboard Viewer, which makes it hard to use if one is not already familiar with it. Here is an online reference that explains how it works.
http://sellinam.com/?p=51
Tamil99 will also not display on Keyboard Viewer in Tiger (Leopard is OK). An alternative keyboard with the same layout as Tamil99, which does display in Keyboard Viewer, can be downloaded here:
http://idisk.mac.com/thgewecke-Public/T99Sub.keylayout
If one selects T99Sub first and then switches to Tamil99, Keyboard Viewer should show the correct layout.
Also available is a layout (TamilPC.keylayout) as used in WinXP. This works differently from the others in that the dependent vowels are input using their own separate keys (aa=e, i=f, ii=r, u=t, uu=g, e=z, ee=s, ai=w, o=`, oo=a, au=q).
To make the Virama (dot above) with the Tamil99 keyboard, you hit the f key.
Note that Adobe and MS products for the Mac (as well as Mellel) cannot do Tamil (or other Indic scripts). You need to use TextEdit, Pages, Nisus Writer Express, NeoOffice, OpenOffice.
If you run into Tamil encoded in the old 8-bit TSCII character set, you may be able to read it by downloading and install one of the fonts from this page.