Sound Controller
 

Is there any software like Volumouse for Windows to control the volume of the system with mouse wheel scroll?

You don't say what version/distro of Linux you're using, or what desktop environment, so it's hard to say.

Best guess: yes. You can do it with the regular volume/mixer icon in KDE, and have been able to for years. Probably the same with Gnome, although I've not tried the new version.

I am using RHEL 6 with gnome.

Ok...so then use the Gnome mixer applet. And since you're using RHEL6, you can call Red Hat support, since you're paying for it, right?? RHEL is a commercial distro. If you're not paying, you WILL NOT get access to updates/patches/bugfixes, and will not be able to use online updates/installer to add new apps. Your system will be unstable and insecure, quickly.

Load CentOS instead...it's virtually identical, and FREE. And unless you have a GENUINE NEED for a server-class distro, load something else. Servers, as a rule, don't have sound, bluetooth, wifi, etc....all the stuff you see on consumer-grade hardware. Naturally, since they don't need it, support is usually lacking. Load Fedora, Mint, Ubuntu, openSUSE, or any other distro instead.