fontsstix
The STIX Fonts Project would provide consistent fonts for some things that are currently missing in LaTeX (e.g. lowercase \mathcal and \mathbb). The website says LaTeX support "will follow in 2011".
Until then is there some way to already use the fonts? Maybe using xelatex instead of pdflatex?
The easiest way to use arbitrary TrueType and OpenType fonts is by using LuaLaTeX or XeLaTeX and fontspec (be sure to use recent versions, as these engines and the fontspec package are still under heavy development).
For example after installing the Tangerine font,
\documentclass{article}
\usepackage{fontspec}
\newfontfamily\textcal[Ligatures=TeX]{Tangerine}
\begin{document}
ABCabc \textcal{ABCabc}
\end{document}
gives 
.
At least with a quick google search I couldn't find an otf or ttf version of Calligra, so you might have to look for a suitable font.
Update your system, then you'll get the old libertine package as libertine-legacy and then it should work as usual. The new package libertineotf supports only xetex and luatex.
With the current TeXLive and MiKTeX as of end of 2012 there is only one package libertine.sty which can be used as
\usepackage[options]{libertine}
Depending on what was run (xelatex/lualatex/pdflatex), it loads by itself the package fontspec or fontenc and does all the configuration.
Best Answer
LaTeX support for STIX fonts (Type 1 fonts, TFM files, support packages, etc) have been released few days ago (currently in beta), for people who want to use STIX but cannot/do not want to switch to a modern TeX engine.