[R] export tables to Excel files

[Ivan Calandra]

Dear R users,

I've just posted a similar question about Illustrator.
This time I would like to export the results of my statistic tables and 
my dataframes into Excel files.

Up to now I've used write.csv(), but I have to resave every file in .xls 
in Excel.
I would like to know if there is a function or package to export 
directly into *.xls.

I have found xlsReadWrite which would be perfect for me, if only I could 
append data to an existing file (I need to do it) and it doesn't work 
with R2.10 (of course the version I use...).
Of course, since I would like to export .xls files, I would have to be 
able to read them too, which means that the package WriteXLS wouldn't be 
enough. And in any case, appending data is not possible.
The package xlsx is not what I need since I still use Excel 2003.

Are there other packages that would correspond to my needs? There might 
also be a better, completely different, approach. I'm open to all 
suggestions of course!

Thanks in advance for your help
Ivan