You can use something like this:
\documentclass{article}
\usepackage[style=authoryear,backend=biber]{biblatex}
\DeclareCiteCommand{\citejournal}
{\usebibmacro{prenote}}
{\usebibmacro{citeindex}%
\usebibmacro{journal}}
{\multicitedelim}
{\usebibmacro{postnote}}
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@article{test,
author = {Author, A.},
year = {2011},
title = {Some relevant article},
journal = {Test journal}
}
\end{filecontents}
\bibliography{\jobname}
\begin{document}
Some text~\citejournal{test}
\printbibliography
\end{document}

EDIT: the following refinements were provided by Audrey:
\citetitle and \citetitle* disable citation tracking. The new command could be defined to be consistent. Generic bibliography macros print the whole title, including subtitles and title add-ons, which can be avoided. A single command could also be used to cite the "main" title of the reference. All this is demonstrated below.
\documentclass{article}
\usepackage{biblatex}
\DeclareCiteCommand{\citejournal}
{\usebibmacro{prenote}}
{\usebibmacro{citeindex}%
\usebibmacro{journal}}
{\multicitedelim}
{\usebibmacro{postnote}}
\DeclareCiteCommand{\citebooktitle}
{\usebibmacro{prenote}}
{\usebibmacro{citeindex}%
\usebibmacro{booktitle}}
{\multicitedelim}
{\usebibmacro{postnote}}
\DeclareCiteCommand{\citeintitle}% Based on \citetitle from biblatex.def
{\boolfalse{citetracker}%
\boolfalse{pagetracker}%
\usebibmacro{prenote}}
{\ifciteindex
{\indexfield{indextitle}}
{}%
\iffieldundef{journaltitle}
{\iffieldundef{booktitle}
{\iffieldundef{maintitle}
{\printfield[citetitle]{labeltitle}}% Behave like \citetitle if no "main" title
{\printtext[maintitle]{\printfield[titlecase]{maintitle}}}}
{\printtext[booktitle]{\printfield[titlecase]{booktitle}}}}
{\printtext[journaltitle]{\printfield[titlecase]{journaltitle}}}}
{\multicitedelim}
{\usebibmacro{postnote}}
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@Article{yoon,
author = {Yoon, Myeong S. and Ryu, Dowook and Kim, Jeongryul and Ahn, Kyo Han},
title = {Palladium pincer complexes with reduced bond angle strain: efficient catalysts
for the Heck reaction},
journaltitle = {Organometallics},
volume = {25},
number = {10},
date = {2006},
pages = {2409--2411}}
@InProceedings{salam,
author = {Salam, Abdus},
editor = {Svartholm, Nils},
title = {Weak and Electromagnetic Interactions},
booktitle = {Elementary Particle Theory},
booksubtitle = {Relativistic Groups and Analyticity},
booktitleaddon = {Proceedings of the Eighth Nobel Symposium},
eventdate = {1968-05-19/1968-05-25},
venue = {Aspen{\"a}sgarden, Lerum},
publisher = {Almquist \& Wiksell},
location = {Stockholm},
date = {1968},
pages = {367--377}}
@InProceedings{moraux,
author = {Moraux, Paul},
editor = {Lloyd, G. E. R. and Owen, G. E. L.},
title = {Le \emph{De Anima} dans la tradition gr{\`e}cque},
subtitle = {Quelques aspects de l'interpretation du trait{\'e}, de Theophraste {\`a}
Themistius},
shorttitle = {\emph{De Anima} dans la tradition gr{\`e}cque},
booktitle = {Aristotle on Mind and the Senses},
booktitleaddon = {Proceedings of the Seventh Symposium Aristotelicum},
eventdate = {1975},
publisher = cup,
location = {Cambridge},
date = {1979},
pages = {281--324}}
@InCollection{pines,
author = {Pines, Shlomo},
editor = {Twersky, Isadore},
indextitle = {Limitations of Human Knowledge According to Al-Farabi, ibn Bajja, and
Maimonides, The},
title = {The Limitations of Human Knowledge According to Al-Farabi, ibn Bajja, and
Maimonides},
shorttitle = {Limitations of Human Knowledge},
booktitle = {Studies in Medieval Jewish History and Literature},
publisher = hup,
location = {Cambridge, Mass.},
date = {1979},
pages = {82--109}}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
\noindent
\citeintitle{yoon} versus \citejournal{yoon} \\\\
\citeintitle{salam} versus \citebooktitle{salam} \\\\
\citeintitle{moraux} versus \citebooktitle{moraux} \\\\
\citeintitle{pines} versus \citebooktitle{pines}
\printbibliography
\end{document}

\citetileor\citetitle*do what you want? – Gonzalo Medina Aug 27 '11 at 22:39