Hotspots are just graphics. Panoweaver support transparent .gif and .png-24 format. You can make them in Photoshop or similar or buy them done.
Panoweaver stores the "default" icons in the library directory within the install directory. You can browse to this directory when adding a hotspot.
C:\Program Files\Easypano\Panoweaver 7 Professional Edition\Libraries\Image\Hotspot
Of course Tourweaver is supplied with more of an assortment because it is a much more powerful tour creating software package.