You do not need an accountant to do your taxes, but it will be a lot easier if you have filed a 1040 for yourself before. It's just the same thing plus a little extra.
Tax write-offs introduction:
You can depreciate the value of the building (not the land), usually by dividing your cost basis on the date the property entered service as a rental by 27.5. So say the building is worth 100k, you would get 100k/27.5 = $3636 in depreciation each year as a deduction.
Whatever amount you pay in mortgage interest is deductible.
Whatever amount you pay in rental insurance is deductible.
Whatever amount you pay in maintenance or service fees like plumbers is deductible.
Your mileage is deductible every time you drive to the rental property for reasons related to property management.
Your gross rental income will get added to your regular job income, and will then be offset by the sum of the deductions above. So if you're charging $1k/month in rent and make $50k/year at your regular job, your new income will be $62k/year minus the deductions listed above.
Tis not that hard. Take an afternoon off and read all about it:
http://www.irs.gov/publications/p527/