I've spoken before of my love for the Octiv/Plantronics Volume Logic audio optimizer plugin for iTunes, which makes your laptop speakers sound like a much bigger system, but when I fired up iTunes under 10.5, unsurprisingly, VL wouldn't work or find its registration info. OK, no problem, surf over to volumelogic.com for an update and... agh! The plugin has been end-of-life'd and Plantronics will produce no more updates. What to do, what to do... time to check out iWOW I suppose -- but what's this?
Credited to VL's 'loyal Mac fans,' an update installer and slighly funky Terminal instructions are available to make VL happy under Leopard, at least for now. Undoubtedly a future iTunes or OS upgrade will break the plugin once and for all, and on that day I will mourn for a moment the departure of VL from my Mac... and then I'll move on.
Update: Note Zach's comment below -- this fix is unsupported and is at your own risk. Per Ronnie's note, a more thorough review of the resolutions is here.