GWAS reviews are a dime a dozen these days, but I found this one in particular that's a good up-to-date review suitable for people relatively new to the field. While this one has a focus on psychiatric genetics, it has a short summary on topics like positional methods, candidate gene studies, common variation, rare variation, CNVs, GWAS design, and issues concerning power and sample size. There's a table defining some basic terminology, a timeline of methods from linkage to the 1000 genomes project, and a table summarizing potentially problematic GWAS design issues.
Genomewide Association Studies: History, Rationale, and Prospects for Psychiatric Disorders (Pubmed)
For other links to send new folks joining your group, check out posts tagged with Tutorials or Recommended Reading.