Sometimes it's very difficult to find deb for an rpm only (or vice versa).
I spent some time searching for a tool to convert .deb to .rpm(still google chrome is ditributed as .deb only).
So I found this tool written in Perl very useful. It's Alien, a script which can convert between .rpm, .deb, .slp and tar.gz(.tgz)
Download it from here .
Unzip it and makesure your system has perl installed and perl version is 5.004 or greater .If not install the latest version by
$sudo apt-get install perl (on Debian distributions)
go into the folder from terminal and type to start installing.
$ perl Makefile.PL
$ make
sudo make install
and it will be installed, and check its man pages for more details.
Its very easy to convert a foriegn package format to the native packaging format of your distribution.
Like
to convert an rpm to .deb on Ubuntu
sudo alien -d file_name.rpm
file_name.deb will be generated.
But converting vice versa is a different story, such as converting a .deb to an .rpm on Ubuntu will give dependency problems. :(
Using verbose option as an command line argument, you can see what alien is doing behind the scenes.

So, no more problems of searching for rpms for deb only softwares :-)
May, Google be with you :P