Okay, so Furox made this kinda thing for Photoshop, so here's the Gimp version!

[EDIT]I'm experimenting with the pspi.exe plugin to use photoshop plugins and filters on Gimp, so check back soon for and easier method!

First, we need to make a pattern for this. Get my image Here
Open it with Gimp, then save it in C:\Program Files\Gimp\Share\Gimp\2.0\patterns as bubbles.pat, set the description as bubbles.
Now, restart the Gimp.
Make a new canvas, 600x600.
Fill it with the bubbles pattern.
Duplicate the layer.
Go to Filters>Distorts>Polar Coordinates and press okay
Use the Choose by Color tool (z) and select the white areas and delete them
Merge the layer down
Now use a Motion Blur (Filters>Blur>Motion Blur) with the following settings

(you'll have to excuse somethings, I made the image then got the screen caps and am using a skin)
Repeat that step (ctrl-F)
Color the layer, I used the Layer>color>colorize tool.
Use the rectangle select tool and make a rectangle on the right side of the screen. Fill it with a neutral color, then copy the selection and delete the bar.
Make a new transparent layer and paste the bar in and move it to the right side.
Go to Filter>Distorts>Wind and use these settings:

Repeat for a while, until about 1/3 of the screen is filled. Now go to Layer>Transform>Rotate 90 degrees CCW
Use the Polar Coordinates again
Now use the select by color tool and delete those white edges.
Use the Motion Blur with the same settings
Now color the layer, feel free to duplicate and make the rays larger through this or make fun colors.
Make a new layer and fill it with black. Go to Filter>Light Effects>FlareFX and click the preview window where you want the flare to go and click okay.
Use the Layers dialog to set the layer to Lighten Only mode.