Hi Adam,
You can define a module setting in a module definition file that allows selecting roles using a built in control.
<featureSetting
resourceFile="YourResourceFile"
resourceKey="RolesThatCanDoFoo"
defaultValue=""
controlType="ISettingControl"
controlSrc="~/Controls/AllowedRolesSetting.ascx"
helpKey=""
sortOrder="350"
regexValidationExpression=""
/>
You then can retrieve the value from Module Settings and check the current user with if(WebUser.IsInRoles(allowedRoles))
Note that this method will always resolve as true for users in the admins role whether you include that role or not
There is also a RoleNotAllowedToEditModuleSettings in site settings > Security > Permissions so you can prevent users from changing the allowed roles.
Hope it helps,
Joe