i found this insanely difficult because none of the supposedly normal options worked. merge modules didn't seem suitable because i just wanted to install the CR dlls once and for all on the server. according to an MSDN2 article
i should be able to perform a windows installer deployment, but of course when i copy the key code from the VS2005 > Help > About dialog, and use it in the installer on the server, the error message is that the key code has expired or is invalid. 'business objects' appear to be forcing users into an upgrade path for their new product, by claiming that a 'compatibility upgrade' is required for VS 2005, which of course you have to fork out for. such a load of crap.
anyway, what eventually worked for me was to go back into my VS 2005 dev machine and create a web set up project. go into the project properties and click the prerequisites button, select CR for .Net 2.0 and then just build the empty setup project. if you look in your output folder, there is an installation file called CRRedist2005_x86.msi. Just whack this onto the server and your crystal reports should run fine, i didn't need to reboot or restart IIS. Note there is no also need to copy any of the CR dlls to your web site bin folder.
yet another miserable failure for crystal reports!