Can you still make a prior year contribution to a Roth IRA until April 15, 2005, if you file your tax return before the April 15th deadline?

Yup, just be sure to designate it as a prior-year contribution so the custodian gets it right.

Tip: Designate the contribution year clearly on your check. Then be sure that the custodian posts it correctly and that the next statement you get is correct. Don't assume that a hassled custodian in the IRA rush will get it right.

So clear it up for me...if a taxpayer physically filed their 2004 tax return on February 15, 2005....can they still make a ROTH IRA contribution up through 04/15/2005 for 2004....as long as the ROTH IRA custodian designates it as a 2004 contribution.

Correct. There's no requirement that the contribution be made before the return is filed. The post-year "grace period" isn't truncated by the filing of the income tax return.