Dear Derek,

If you want a good-looking, free diacritic font for romanized Skt / Pali,
try Gentium -- that's the one I use for day-ti-day work unless I need
non-Roman scripts. Don't have the URL but try googling for it.
Alternatively, try the Gandhari font. A free alternative to MS Arial
Unicode is the mega-font produced by the German TITUS project -- again try
googling for it.

Best wishes,
Stephen Hodge