I've found a ton of Photoshop tutorials on how to do this, but you would be surprised at how simple and easy it is to get a “glossy” text effect in vector using Illustrator. Don't get out of your seat, because this won't take long at all.
1. Outline your text
The first step is to outline your text to make it a into an actual shape. This is assuming that you already have your logo text and font picked out. To outline, make sure you have the text selected, and go to Type>Create Outlines.
Here is the text outlined.
2. Offset your path
Offset Path in Illustrator takes the current path, duplicates it, and makes it however many pixels you choose bigger or smaller in every direction. It isn't quite the same as simply scaling up/down. It makes a path inside or outside of the current path using a specified distance between the paths. The reason we will be using offset path is because, well . . . it's just plain easy to do. Yes, you could just make another shape below and add a stroke, but that is altering the font a bit, and most of the time, you probably don't want to do it that way. Instead, with your outlined text shapes selected, go to Edit>Path>Offset Path.
Now you are given some options for the Offset Path. Here you have precise control over the path being created inside of your outlined text. Enter a negative value in order to make the offset “inside” the original.
Click OK and there Illustrator does all the work for you. Zoomed in view of the -2px offset path:
3. Fill your new path with white
Your new offset path should still be selected after you clicked OK, so now is the perfect time to make your fill. I used white, generally the universal “glossy” color.
4. Make your cut
With the rectangle tool, make a white rectangle that covers the part of the reflection you would like to remain visible.
Now, this is why I used a “white” rectangle. with the square still selected, go to Select>Same>Fill Color, and you will have selected everything you need for the cut. Otherwise, you will need to select all of the shapes with the white arrow.
Before making your cut, make sure you have all of the correct paths selected:
Hit the “Crop” button in the Pathfinder window to get rid of all the paths that are outside of the rectangle. (Window>Pathfinder)
Our new reflection shape has now been made
5. Adjust the opacity
You probably want to adjust the opacity a bit to get the look you are after.
If you would like to learn how to make the reflection itself “fade” out with a transparency gradient, read this post on making an Opacity Mask in Illustrator.
Here is a post on how to make a Fading Logo Reflection in Illustrator.