You can get a soil test kit at Home Depot or Lowe's and do it yourself, or you can take a soil sample to your County Extension office to be tested. If you want more than one sample (eg. from several places around your yard) it's much more efficient and cost effective (here they charge $5 per test) to get a kit of your own. The kit to do 10 tests was about $10 last time I bought one - a long time ago.
