For plus sized beach dresses, visit http://www.alwaysforme.com/coverups2.html. They offer matching cover-ups and sun dresses for your swim wear to complete your outfit for the trip to the beach.
You can try going to David's Bridal if there are any in your area. Or you can find cute plus sized prom dresses in regular department stores such as JCPenny
You can find plus sized dresses at big department stores websites such as JC Penny, Macy's Women, Sears, Kohls, Designer Warehouse, and other sites as well.
Places like Overstock, Forever 21, Torrid, and Nordstrom not only offer plus size options in terms of dresses for plus sized women, but they also offer leopard print dresses in plus sized sizes.
Lane Bryant.
You can find plus sized dresses for a child by going to Jeeny Beans, Sears, Bonnie Jeans, and Old Navy, Gap, and Elegant Plus. You can shop on amazon.com.
Macys.com has a large selection of plus sized dresses. Many are also at a very affordable price for those looking for cheaper dresses.
Sydney's Closet (http://sydneyscloset.com) and The Rose Dress (http://www.therosedress.com) sells plus-sized formal dresses.
There are actually a lot of plus size stores around nowadays, you can find them at most malls or shopping centers. How much the clothes cost will vary from store to store. Here's a website link to a plus sized store that has good prices on a variety of dresses. http://www.avenue.com/
For plus sized wedding dresses in New York, you can try Kleinfeld or even Lane Bryant. You can also try The Bridal Building or Bridal Suite of Manhattan.
There are several online stores/catalogues for plus sized dresses of various styles for various occasions. Try evogues.com, plussizethis.com, elegantplus.com, amazon.com, overstock.com.
For a formal plus sized dress, Igigi is the place to go. Their site is http://www.igigi.com. You can also find nice plus sized dresses at Lane Bryant and Torrid. Both have online sites you can look through as well.
Through my research, I've found that David's Bridal offers the largest selection of plus sized wedding dresses. Their website alone offers over twelve pages of plus sized wedding dresses in all different styles. David's Bridal is also a store that can be found in many different locations and their prices are very reasonable. Here is a direct link to David's Bridal's plus sized section: http://www.davidsbridal.com/Browse_Bridal-Gowns-Shop-By-Size-Plus-Sizes