Umlauts, cidillas and accents galore

My english speaking user community wants to store names of books and articles, "bibliographic reference data" ,so called, which may be in western european languages other than English, or transliterated into a latin character set from non latin alphabets possibly decorated with all manner of accents, umlauts, and other diacritical (sp?) marks.

Clearly, the "charset" parameter of the database must specify a character set large enough to include all the desired characters. I suppose UTF8 will fit the bill but maybe its overkill and we can get away with WEISOxxxxxx ?

The real fun comes when we want to make a query. Our users would like to search
for something "like" 'Frederic" and not get a null result when the data is actually
the French Frederic with acute accents instead of plain vanilla "e".

Will we have to hold both "decorated" (i.e. with diacritical marks) and
"undecorated"

(without the marks) so that we can query the "plain" and return the
"decorated" ;or is there something more clever or more elegant?

If I have a UTF8 data set including characters with accents, and do a query via sql plus, will sql plus be able to render the result with the proper characters or does that depend on a host (no pun) of things such as the client machines operating system, code page, language settings and things I dont know about?

While we're at it, how does one go about getting the "funny" characters into the
database in the first place? Does one need to compose the characters with "Alt" keystroke, keystroke (yuk!) or are there tools out there to make that smoother or what?

Can anyone sort me out on that, or if that would be too lengthy a response, at least point me to some appropriate literature so that I'm not talking completely through my had about what can be done and how one might do it?

Sorry to be so long winded, but I've waded through what seems like Oceans of literature about Unicode, Oracle NLS parameters, multi lingual web sites and such like, and I'm still surrounded by clouds of bewilderment.

Thanx in advance