Assuming you can modify the class that is used in the collection, I would make a "display" property.
public string Prop1 { get; set; }
public string Prop2 { get; set; }
public string PropertiesFormatted
{
get
{
return this.Prop1 + " - " + this.Prop2;
}
}
You can then assign that to a bound column. I find that this is better since you won't have to worry about having the formatting different in different areas of the software. Basically, it allows for reuse.
The other way to do it would be to indeed create a template column and using binding expressions. You can find out about data binding expressions either on MSDN or in Telerik's help, but you're going to want to do something like this:
<telerik:GridTemplateColumn UniqueName="TemplateColumn">
<ItemTemplate>
<span><%# DataBinder.Eval(Container.DataItem, "Prop1") %> - <%# DataBinder.Eval(Container.DataItem, "Prop2") %></span>
</ItemTemplate>
</telerik:GridTemplateColumn>
EDIT
Here is a URL that will allow you to look at some Grid template stuff: http://www.telerik.com/help/aspnet-ajax/grdcustomizewithgridtemplatecolumn.html