Hi Nelson, you could try bquote. For example 

main.title

Hi Nelson, you could try bquote. For example 

main.title

Thanks alot. It works perfectly.

I think there also exists one, perhaps primitive, but effective way. If you are a frend of Photoshop, Adobe Illustrator or an equivalent program, you can print the original, skan it and than you have unlimited chance to apply your graphical invention and phantasy.. Even using ctylics or fracture

another, more commonly suggested way, is with substitute, e.g. 

substitute("Relative efficiency for sample size " * {italic(n) == ni}, list(ni=n[i]))

from a post in the R help  archive : https://stat.ethz.ch/pipermail/r-help/2008-June/163569.html

Note that something like printing in italics should be covered in pretty much all the basic resources, a choice of free ones is listed on the R web site

http://cran.r-project.org/other-docs.html