Since this topic comes up every now and again, allow me to point out a resource I just happened upon:
http://www.bitjungle.com/~isoent/
On this page is a link to an XML file that is a very thorough database mapping Unicode code points (at least, ones that we care about) to their LaTeX representation. When the LaTeX representation requires a particular package or environment, these are provided. For example:
<char pos="840">
<entity name="Kcy" set="iso-8879-cyr1">
<desc>=capital KA, Cyrillic</desc>
</entity>
<unicode value="041A">
<desc>CYRILLIC CAPITAL LETTER KA</desc>
</unicode>
<latex>
<seq req="cyracc,amsfonts" env="cyr">K</seq>
<seq req="fontenc:T2A">\CYRK</seq>
</latex>
</char>
This is the mapping to end all mappings. It evens comes with convenient PDF references.
···
--
Robert Kern
rkern@...170...
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter