If by rotating in a circle you mean WALKING on top of the circumference of a circle, then I guess any of the answers correctly answered your question. So here is my add:
You can continue loading you texture with
texture = new Texture(Gdx.files.internal("1325603701_wordpress.png"));
but it is extremely recommended that you use the AssetManager. About it not loading in the emulator, check if your texture size is power of two. (Like 64x64)
Then create your sprite:
sprite = new Sprite(texture);
you'll possibly want to pass more arguments to cut the sprite, in case you're using a power of two texture for a non power of two sprite.
Create a helper variable on the class body, to keep track of the time, and one to say where will be the sprite center:
private float elapsedTime = 0.0f;
private Vector2 center = new Vector2(10, 10);
on render:
public void render () {
final float speed = 30.0f; // in degrees per second
final float radius = 10.0f; // the radius of the circle you'll be rotating
float angle = elapsedTime * speed;
Gdx.graphics.getGL10().glClear(GL10.GL_COLOR_BUFFER_BIT);
spriteBatch.setProjectionMatrix(camera.combined);
spriteBatch.begin();
sprite.setRotation(angle - 90);
sprite.setPosition(center.x + radius * (float)Math.cos(angle * MathUtils.degrad), center.y + radius * (float)Math.sin(angle * MathUtils.degrad));
sprite.draw(spriteBatch);
spriteBatch.end();
}
This should work just fine.