Don't we need to understand the origin of life before we can understand evolution? No.

Understanding abiogenesis, the origin of life, is not required for understanding evolution, the diversification of life given that life exists. What's required for evolution is self-replicating systems with a mechanism of inheritance, and occasional imperfections in the process of self replication. 

Regarding abiogenesis, creationists have been fond of pointing out problems with self assembling molecules, replication of peptides without DNA, replication of nucleotides without enzymes, and getting homochirality from random mixtures both right and left handed molecules. In fact, considerable progress has been made on each of these questions.

Here are some references:

Self assembly:

Jason P. Dworkin, David W. Deamer, Scott A. Sandford, and Louis J. Allamandola 2001. Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices. Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 3, 815-819, January 30, 2001 (link)

Self replicating nucleotides without enzymes:

Wendy K. Johnston, Peter J. Unrau, Michael S. Lawrence, Margaret E. Glasner, David P. Bartel. 2001. RNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension. Science 292: 1319-1325 (PubMed, full article)

Xiaoyu Li, Zheng-Yun J. Zhan, Rachel Knipe, and David G. Lynn 2001. DNA-Catalyzed Polymerization. J. Am. Chem. Soc., 124 (5), 746 -747 (link)

A. Luther; R. Brandsch; G. von Kiedrowski. 1998. Surface-promoted replication and exponential amplification of DNA analogues. ; Nature Volume 396 Number 6708 Page 245 - 248 (1998). (link)

Bag BG, von Kiedrowski G 1999. Stepwise Replication of a Troger's Base Analogue. Angew Chem Int Ed Engl 1999 Dec 16;38(24):3713-3714. (link)  

Scheffler M, Dorenbeck A, Jordan S, Wustefeld M, von Kiedrowski G 1999. Self-Assembly of Trisoligonucleotidyls: The Case for Nano-Acetylene and Nano-Cyclobutadiene. Angew Chem Int Ed Engl 1999 Nov 15;38(22):3311-3315. (link)

Sievers D, von Kiedrowski G 1994. Self-replication of complementary nucleotide-based oligomers. Nature 1994 May 19;369(6477):221-4. (link)

Self replicating peptides without DNA:

Saghatelian A, Yokobayashi Y, Soltani K, Ghadiri MR. 2001.A chiroselective peptide replicator. Nature 2001 Feb 15;409(6822):797-801 (link, link)

Lee DH, Granja JR, Martinez JA, Severin K, Ghadri MR. 1996. A self-replicating peptide. Nature 1996 Aug 8;382(6591):525-8 (link)

Homochirality:

Josep M. Ribó, Joaquim Crusats, Francesc Sagués, Josep Claret, Raimon Rubires. 2001. Chiral Sign Induction by Vortices During the Formation of Mesophases in Stirred Solutions. Science  Volume 292, Number 5524, Issue of 15 Jun 2001, pp. 2063-2066. (Abstract)

Rubires R, Farrera JA, Ribo JM. 2001. Stirring effects on the spontaneous formation of chirality in the homoassociation of diprotonated meso-tetraphenylsulfonato porphyrins. Chemistry 2001 Jan 19;7(2):436-46 (PubMed)

Robert M. Hazen, Timothy R. Filley, and Glenn A. Goodfriend. 2001. Selective adsorption of L- and D-amino acids on calcite: Implications for biochemical homochirality. Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 10, 5631-5636, May 8, 2001 (abstract, link)

http://www.ch.cam.ac.uk/CUCL/staff/ajm.html

Other articles of interest:

Keefe, A. D. & Szostak, J. W. "Functional proteins from a random-sequence library". Nature 410, 715-718 (2001) (PubMed)

Stephen J. Sowerby, Corey A. Cohn, Wolfgang M. Heckl, and Nils G. Holm 2001. Differential adsorption of nucleic acid bases: Relevance to the origin of life. Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 3, 820-822, January 30, 2001 (link)

http://www.chem.rpi.edu/chemweb/new/faculty/people/ferris/Ferris.html

Clarke DW, Ferris JP. 2001. Chemical evolution on Titan: comparisons to the prebiotic earth. Orig Life Evol Biosph 1997 Jun;27(1-3):225-48 (PubMed)

MARK A. SEPHTON 2001. Meteoritics: Life's sweet beginnings? Nature 414, 857 - 858 (2001) © Macmillan Publishers Ltd. (link)

GEORGE COOPER*, NOVELLE KIMMICH*, WARREN BELISLE*, JOSH SARINANA*, KATRINA BRABHAM* & LAURENCE GARREL 2001. Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth. Nature 414, 879 - 883 (PubMed, link)