For music shareware SharewareMusic Machine is a very good place to start for any platform, and theSoftware Archive Sites page has plenty of links you cancheck out. K-v-R supports open standard audio plugins and is a great source of plugin information.
If you are using Windows then MIDI-OX is essential sysex software for sending and receiving patch data with your MIDI synthesizer. If you are using Mac OS X get SysEx Librarian.
If the website you desparately wish to find has disappeared you may be able to visit an archived version of it in the past using the Wayback Machine.
SynthZone is an attempt to ease the search for synthesizer & electronic music production resources on theInternet. For more info read the SynthZone FAQ.
Korg Kronos sets a new standard for electronic keyboards. Alesis present StudioDock a universal docking station specifically designed for the iPad.MIDI Mobilizer adds MIDI connectivity to iPad, iPhone and iPod Touch.
Band In A Box for iPhone extends the usefulness of BIAB desktop. Jam2Jam is collaborative media performance software.Sympheo is a CSound synthesis graphic interface oriented to music composition.