"Lymph glands" is lazy terminology; I've never heard an immunologist use that term, though I've heard it used in medicine to mean lymph nodes.
Lymph nodes are located all over the body. They contain B and T lymphocytes. They process lymph (fluid from bodily tissues). The lymph is "percolated" through the lymph node. When there's an infection, B and T cells specific for the antigen (the virus, bacterium, parasite, or whatever) proliferate in the lymph node. This causes the palpable swelling that your doctor checks for when you're sick. They can be felt easily in the armpit, the groin, the neck and and jaw area, and behind the ear, but they're found in other places as well.
Some more information on lymph nodes (as well as a diagram showing where they're found in the body) can be found at: [url="http://www.cayuga-cc.edu/about/facultypages/greer/biol204/lymphatic2/lymphatic2.html"]http://www.cayuga-cc.edu/about/facultypages/greer/biol204/lymphatic2/lymphatic2.html[/url]
Glands (examples: adrenal, thyroid, pituitary) are endocrine organs that secrete hormones into the bloodstream. More on glands and the endocrine system can be found here: [url="http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookENDOCR.html"]http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookENDOCR.html[/url]