Greetings all,I have a "real" full-time job and also do some sole-proprietor-type work on the side that generates a moderate amount of income for me. I've maxxed out on the ROTH and am trying to figure out another option for retirement investing besides the 401(k) since my employer does not match.I've done preliminary reading on the SIMPLE IRA. Does anyone have experience with this? It seems I can use this as a self-employed, sole-proprietor; however, do I need to have been making contributions all year long, or can I make a contribution at the end of the tax year? Any help would be appreciated--I've looked all over and remain confused.Thanks in advance!