One disadvantage of using Internet Explorer as a browser as opposed to say Firefox is the absence of a built in client side spell checker. With CRM 4.0 working exclusively with Internet Explorer, spell checking becomes more than just a convenience but a necessity since Activities entered into the CRM are viewable by co-workers throughout your organization. One creative spell checking solution which utilizes Microsoft Office's spell checking capabilities through an ActiveX control is outlined on CRM MVP Jim Wang's blog. However, this solution requires some relaxation of ActiveX control security within IE in addition to unsupported modifications to the edit.aspx page on your CRM server. An alternative is to install the free lightweight IE addon, IE7Pro. IE7Pro is not affiliated with Microsoft but is built and maintained by Innoshock, a small group of independent developers.

Much like Firefox, IE7Pro generates revenue by creating a Google search bar and generating search referral traffic. This allows Firefox and IE7Pro to operate advertisement free since Google pays them for any link ads you click through your searches. As a result, you the end user get a great suite of add-ons for Internet Explorer. Using the IE7Pro search bar is optional and can be turned off within the settings. You'll want to configure IE7Pro as shown in the screen shot below, since in this post we are only interested in the spell checking feature.

Some of the pros and cons to using IE7Pro over Jim Wang's Microsoft Office solution are outlined here:
Pros for using IE7Pro:

• Spell check as you type
• Fully functional and free of charge
• No chance of breaking in future CRM update rollups and upgrades
• Does not use ActiveX, so no need to relax ActiveX security settings in IE
• Non technical, no coding required, easy button click install
• Spell checking not limited to just CRM 4.0

Cons for using IE7Pro:

• No suggestion list for incorrectly spelled words
• Must individually install/maintain on user computers
• Might not catch all spelling errors(missed my errors with text and numbers e.g. "gr8")

I've found IE7Pro to be great at what it does, simple IE spell checking and your CRM 4.0 users should too!