Use Antares' Autotune plug-in not only to correct vocal pitching, but also to tune up
guitar solos and especially bass track. As long as you set a slow enough tracking time, regular playing will be unaffected, but whenever you sustain a note, it
will automatically settle on exactly the right pitch. This can be particularly useful for slow
pieces that use a lot of string bends or slow bass parts where one note lasts for a few bits or more.

See Autotune here:

www.antarestech.com