Oracle 10g/11g webgate software download location
WebGate is Web Server plug-in which communicates between WebServer (OHS, Apache, IIS, IHS..) and OAM Server (Access Server in 10g and Proxy-Port in 11g).
There are two version, 10g WebGate and 11g WebGate (both 10g and 11g WebGate then have Bundle Patch like WebGate 10g BP10 or WebGate 11g BP01)
10g WebGate works with both 10g OAM (Access Server) and 11g OAM (Access Server) where as 11g WebGate works only with 11g OAM Server (Access Server).
If you are looking for WebGate software then
Note: Currently (as of Nov 2011) 11g WebGate is available only for Oracle HTTP Server (OHS) 11g. If you wish to integrate other web servers (Apache, IBM HTTP Server, IIS or OHS 10g) with OAM 11g then use 10g WebGate.