Check out the link & video.
If you want to diy its not a real big deal.
http://www.wooferrepair.com/faq.html
Sorry i posted too fast,if you just want a quick & lasting repair without removing the driver its an easy fix,there is a sealent(caulking) called "Vulkem" that is perfect for repairing foam or rubber surrounds,its not like regular home owner silicone caulk junk that just peels right off after it dries,you are never getting Vulkem off anything you put it on as long as the surface is dry.
Vulkem is a polyurethane sealent & comes in a regular caulking tube,it also comes in a ton of colors including black & can be found at any professional contractor supply or glass shop for about $6,home depot or lowes are not pro builders suppliers & will not carry this item but its easy to find.
Heres a link to find where to buy in your area,if you do decide that you want to use this product & you cant find any local to you i can send you a tube of black if you like.
http://www.tremcosealants.com/commercial/where.asp