KnittingHelp.com and KnittingPatternCentral.com offer hundreds of free knitting patterns for dishcloths. Both KnitPicks.com and AllCrafts.net also have large selections of free dishcloth patterns of varying skill levels.
Ravelry.com has thousands of free knitting patterns for dishcloths available, but a free account is required to have access to them. All of the free pattern websites have a large variety of patterns to choose from. The range of difficulty includes patterns that require almost no skill to complete and patterns that require more advanced techniques to complete. All the patterns are marked with the required skill level and include a supply list and all necessary instructions.