OpenSIPS (former OpenSER) is fastest open source implementation of a SIP proxy.
Recently I added new rpm-package opensips-1.6 to fedora. OpenSIPS can be installed parallel with current openser package. At the moment package is pending to adding to updates for F-11.
People who want to use db_oracle module should to install proprietary instantclient-sdk-10.2.0.3 from Oracle and to rebuild package with --with-oracle rpmbuild option. Then opensips-oracle rpm package will be available to install.
Thanks Peter Lemenkov for help and package review.
UPD: package is pushed to stable updates.